I have a couple of linear PSU's (Weir, both 30V-2A, 15V-4A) but they
are both old and are now non-functional / iffy and I was considering
something newer, lighter, smaller and with twin digital displays (on
the Weir's you have to switch between displaying V and A).

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

It's for general use, (temporarily) powering 5/12V things, charging
the odd battery and the like.

A 10A capacity might mean it can batter handle a 5A output, quieter
the better (some use small heatsinks and small fans) and ideally under
say £100?

I did look at kits (good to know you have the cct diagram) but that's
probably not best done with a SMPSU and linear stuff also seems to
require large heatsinks and heavy switching devices, all taking extra
time to source/ build (unless a complete kit with case / hardware
etc).

Cheers, T i m

In message , T i m
writes

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

I, and quite a few people I know, regularly use units from Maplins and
Circuit Specialists (Europe) with excellent results, although our use is
operating ancient (open frame) and modern (can) electric motors (toy
trains), where voltage requirements can be anywhere from 4 to 30, and
amps less than an amp to 5 amps.

I don't think the Maplin units are available unused now, but CSE units
are :

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

--
Graeme

On Tue, 15 Sep 2020 15:31:23 +0100, Graeme
wrote:

In message , T i m
writes

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

I, and quite a few people I know, regularly use units from Maplins and
Circuit Specialists (Europe) with excellent results,

I forget about Maplins these days. ;-(

although our use is
operating ancient (open frame) and modern (can) electric motors (toy
trains), where voltage requirements can be anywhere from 4 to 30, and
amps less than an amp to 5 amps.

Yes, something I discovered when automating a section of BIL's model
railway layout with an Arduino and using PWM. On the same settings,
one loco would hardly move and another would fly off the track!

I don't think the Maplin units are available unused now, but CSE units
are :

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

That's spooky Graeme, that looks *exactly* the same as the one my mate
had in his PC shop and *we* used many times, till he sold up (and took
it with him). ;-(

My only criticism of it (and we shared it actually) is that it was
easy to grab the 'Coarse' rather than 'Fine' knob if you were doing
something on the fly. Apart from that, it always did what we asked of
it and was pretty compact (and being portrait rather than landscape,
took up very little shelf space). ;-)


Highly recommended.

That's the sort of thing I was hoping for, thanks. ;-)

10amp unit also available.

Looking at the price difference (nearly double) and assuming the 5A
model really can source 5A continuously (for 8 hours it says) then I
might just go with that, certainly for now.

Cheers, T i m

p.s. With the advent of all these electric scooters and cycles, some
of which running 36V+ battery systems I'm wondering if a 50V (3A)
might be of use to me? Circuitspecialists do a 50V / 3A linear PSU
that just sneaks in under my price limit. ;-)

My iCharger can 'boost' the output voltage over the input voltage:
https://www.icharger.co.nz/icharger-1010b
And has the balance feature so I might stick with that for the
batteries.

Graeme formulated on Tuesday :
I don't think the Maplin units are available unused now, but CSE units are :

https://www.circuitspecialists.eu/power-supplies/bench-power-supplies/switch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/
;

Highly recommended. 10amp unit also available.

My Maplin unit recently took out it's voltage/current sensing IC,
repaired now and I suspect it was just an isolated failure of the IC.

In message , T i m
writes
On Tue, 15 Sep 2020 15:31:23 +0100, Graeme
wrote:

Highly recommended.

That's the sort of thing I was hoping for, thanks. ;-)

Tim, should you ever see an advert for a vintage train show, almost any
display running 0 gauge or larger will be using Maplin or CSE units. I
belong to various groups and hear nothing but praise for them, and use
them myself.

There are others, designed for the job, that are just not up to it,
particularly all day events, to the extent that people build frames with
cooling fans to prevent overheating and cut out. No such problems
reported with the Maplin/CSE units. I have also found CSE to be
approachable and helpful, should the need arise.

Cheers,
--
Graeme

In message
Graeme wrote:

In message , T i m
writes

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

I, and quite a few people I know, regularly use units from Maplins and
Circuit Specialists (Europe) with excellent results, although our use is
operating ancient (open frame) and modern (can) electric motors (toy
trains), where voltage requirements can be anywhere from 4 to 30, and
amps less than an amp to 5 amps.

I don't think the Maplin units are available unused now, but CSE units
are :

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

I have and use the CSI 3005T 30volt 5amp version
Definitely recommended, it charged my car battery no probs.

--
John Bryan

On Tuesday, 15 September 2020 15:31:41 UTC+1, Graeme wrote:
In message , T i m
writes

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

I, and quite a few people I know, regularly use units from Maplins and
Circuit Specialists (Europe) with excellent results, although our use is
operating ancient (open frame) and modern (can) electric motors (toy
trains), where voltage requirements can be anywhere from 4 to 30, and
amps less than an amp to 5 amps.

I don't think the Maplin units are available unused now, but CSE units
are :

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

Had a look as I want one too. It doesn't give any clue whether the adjustable current limit shows what it's set to or whether it's adjusted blind. I therefore expect it's the latter. Also beware the 0.2v ripple spec! Also zero info on meter accuracy.


NT

On Tue, 15 Sep 2020 17:16:12 +0100, Graeme
wrote:

In message , T i m
writes
On Tue, 15 Sep 2020 15:31:23 +0100, Graeme
wrote:

Highly recommended.

That's the sort of thing I was hoping for, thanks. ;-)

Tim, should you ever see an advert for a vintage train show, almost any
display running 0 gauge or larger will be using Maplin or CSE units. I
belong to various groups and hear nothing but praise for them, and use
them myself.

I think that does usually suggest they have found a good solution. ;-)

There are others, designed for the job, that are just not up to it,
particularly all day events, to the extent that people build frames with
cooling fans to prevent overheating and cut out.

Oh. ;-(

No such problems
reported with the Maplin/CSE units.

Similar with RC racing car gear. You often see all sorts of gear at
the beginning of a season but they gradually refine towards just a few
models towards the end.

I have also found CSE to be
approachable and helpful, should the need arise.

That was another question so thanks. ;-)

OOI, do we think that the models shown on the CSE site are in any way
different to those (exact looking) sold via the likes of eBay or
Amazon etc? Not that CSE's prices aren't competitive etc?

Cheers, T i m

On Tue, 15 Sep 2020 17:36:45 +0100, John Bryan
wrote:

snip

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

I have and use the CSI 3005T 30volt 5amp version
Definitely recommended, it charged my car battery no probs.

Excellent, thanks for the feedback and another vote for CSI.

Did you go for the linear one for a specific reason may I ask John and
if so, what OOI?

Cheers, T i m

On Tue, 15 Sep 2020 11:25:00 -0700 (PDT), wrote:

Had a look as I want one too. It doesn't give any clue whether the
adjustable current limit shows what it's set to or whether it's adjusted
blind. I therefore expect it's the latter.

There is a link to download the manual. Which doesn't tell you
anything about how to operate it! Like how to set it to CV or CC
mode, etc

Also beware the 0.2v ripple spec!

And being SMPSU "ripple" at few 10's of kHz? Doesn't bode well for
how much RFI it chucks out.

Also zero info on meter accuracy.

I can see
3 digits
A nd V "LCD +/- 1% +2 Digits".

--
Cheers
Dave.

used his keyboard to write :
Had a look as I want one too. It doesn't give any clue whetherer the
adjustable current limit shows what it's set to or whether it's adjusted
blind.

Yes, blind, but you can work around it by shorting the output and
gradually increasing the current limit to what you want.

On Tue, 15 Sep 2020 11:25:00 -0700 (PDT), wrote:

snip

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

Had a look as I want one too. It doesn't give any clue whether the adjustable current limit shows what it's set to or whether it's adjusted blind.

I therefore expect it's the latter.

By shorting the output out and then adjusting it? Is that what you
mean by 'blind' or did you mean more 'on the fly'?

Also beware the 0.2v ripple spec!

What would that affect, ITRW and is it only likely (to be that high a
value) to be at full load?

Also zero info on meter accuracy.

It's a 50 quid PSU. ;-)

Cheers, T i m

In message
T i m wrote:

On Tue, 15 Sep 2020 17:36:45 +0100, John Bryan
wrote:

snip

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

I have and use the CSI 3005T 30volt 5amp version
Definitely recommended, it charged my car battery no probs.

Excellent, thanks for the feedback and another vote for CSI.

Did you go for the linear one for a specific reason may I ask John and
if so, what OOI?

Cheers, T i m

No I wanted one where the current limit was fully adjustable, which on my
model it is 0.001A to the max of 5.200A.

the adjustment of voltage or current is achieved by pressing in the
control knob to select the decade 10V.1V.0.1V,0.01V and turning the
encoder shaft to to desired value. Current setting likewise but
1A,0.1A,0.01A and 0.001A units.



--
John Bryan

On Tuesday, 15 September 2020 20:03:22 UTC+1, Dave Liquorice wrote:
On Tue, 15 Sep 2020 11:25:00 -0700 (PDT), tabbypurr wrote:

Had a look as I want one too. It doesn't give any clue whether the
adjustable current limit shows what it's set to or whether it's adjusted
blind. I therefore expect it's the latter.

There is a link to download the manual. Which doesn't tell you
anything about how to operate it! Like how to set it to CV or CC
mode, etc

correct, though I would not expct there to be any separate CV or CC modes. With bench psus one simply sets the 2 limits.


Also beware the 0.2v ripple spec!

And being SMPSU "ripple" at few 10's of kHz? Doesn't bode well for
how much RFI it chucks out.

0.2v of ripple is terrible for a bench psu. It seriously compromises what it can be used for. It does not lead me to conclude this is a competent unit.


Also zero info on meter accuracy.

I can see
3 digits
A nd V "LCD +/- 1% +2 Digits".

So upto 30.0v
+/- 1% is 0.3v
and 2 more digits is +/- a total of 0.5v. That's terrible. No good for me anyway.

Good enough to run motors, but not as a multipurpose bench psu.


NT

On Tuesday, 15 September 2020 20:56:16 UTC+1, T i m wrote:
On Tue, 15 Sep 2020 11:25:00 -0700 (PDT), tabbypurr wrote:

snip

https://www.circuitspecialists.eu/po...er-supplies/sw
itch-mode-dc-bench-power-supply-adjustable-0-30v-0-5a-csi-3005sm/

Highly recommended. 10amp unit also available.

Had a look as I want one too. It doesn't give any clue whether the adjustable current limit shows what it's set to or whether it's adjusted blind.

I therefore expect it's the latter.

By shorting the output out and then adjusting it? Is that what you
mean by 'blind' or did you mean more 'on the fly'?

Also beware the 0.2v ripple spec!

What would that affect, ITRW and is it only likely (to be that high a
value) to be at full load?

Also zero info on meter accuracy.

It's a 50 quid PSU. ;-)

Cheers, T i m

Quite. Even rock bottom £2 multimeters have specs. No specs makes the readings fairly meaningless.


NT

On Tue, 15 Sep 2020 21:39:56 +0100, John Bryan
wrote:

snip

Did you go for the linear one for a specific reason may I ask John and
if so, what OOI?


No I wanted one where the current limit was fully adjustable, which on my
model it is 0.001A to the max of 5.200A.

So that was a 'yes' then, the current limit thing. Bit isn't that
available on most 'current limiting' PSU's, even if they aren't so
easy to apply (without shorting the output) or as accurate to set?

I think most people use the current limit as a fuse or to limit the
current for charging a car battery, where I don't think you need so
much accuracy etc? It could be important when charging a very small
battery etc.

the adjustment of voltage or current is achieved by pressing in the
control knob to select the decade 10V.1V.0.1V,0.01V and turning the
encoder shaft to to desired value. Current setting likewise but
1A,0.1A,0.01A and 0.001A units.

I checked out the PSU you have on Youtube and saw that in action and I
was wondering how easy / fast it was to use in practice, compared with
a straight linear knob etc (the only type I've used).

If I use my Weir linear PSU as an example and charging a car battery.
If the battery was a reasonable size then I'd just wind the current to
max (assuming a 5A PSU), set the voltage to maybe 14V and connect up.
If it was as smaller capacity battery (say off a motorbike) I might
want to limit the current to 1A then I'd just turn the current knob up
or down till it reads 1A. If it's already fully charged it may only
take 1A (at 14V) for a few seconds in any case.

An example of where the selection method of the PSU you have was shown
on the Youtube video was where he set a very fine current limit to
drive a LED, saves having to bother with a series resistor etc.

I guess it might all boil down to how accurately you want to control
the voltage and current and how often you are changing it (along with
any other characteristics etc).

My Weir PSUs have a single analogue meter on the front (albeit quite a
big one) that you switch between volts and amps (triple reading scale
as it can go 0-15V and 0-30V, plus amps etc) and I've found it
sufficient for most of the stuff I've used it for so far. If I want
more voltage accuracy I just stick a DMM on the thing I'm powering.

The control knobs feel like they are wire would so probably quite
expensive. I just prefer the digital display and am not sure I need to
go down to that level of accuracy .01 V/A?

That's for bringing it to my attention though and I will consider it
further. ;-)

Cheers, T i m

On Tue, 15 Sep 2020 15:13:30 -0700 (PDT), wrote:

snip

Quite. Even rock bottom £2 multimeters have specs. No specs makes the readings fairly meaningless.

Depending on what you use the PSU for.

All my PSU's so far have been linear and with analogue displays and
controls and so the setting accuracy was really down to the analogue
meter and the granularity of the control knobs.

Two Weirs are built like an old skool radio with lots or wires and a
fairly large PCB and given most of the stuff on there is likely to be
good (or easily replaced), I was wondering if I couldn't take the most
faulty one and 'upgrade' it with an LM338 or similar?

I could replace the analogue meter with two digital ones (or a dual
one) but I could stick with the analogue meters to start with as
that's less to do.

The only thing is it's currently able to be split rail or 0-30 so I'd
probably lose the spilt bit (not sure I've ever used it).

Ideally I'd like a kit PCB with all the components on that aren't
already in the Weir and start from that. At least I could fault find
it if / when it goes wrong. ;-)

I have seen one that suggests the LM338 can be 0-30V and 5A so I could
limit the current to 4A to match the existing meter and allow it to
run cooler (it has a large passive heatsink across the back).

Cheers, T i m

p.s. I think I'll still go for one of the basic SM PSU's and I'm sure
it would be fine for most my needs and I've used one before.

In message , T i m
writes

OOI, do we think that the models shown on the CSE site are in any way
different to those (exact looking) sold via the likes of eBay or
Amazon etc? Not that CSE's prices aren't competitive etc?

I think they are identical, although I don't have two units from
different sources side by side to compare. Speaking to friends, some
have purchased via Amazon or eBay and some (like me) direct from CSE,
and all seem the same.
--
Graeme

On Wed, 16 Sep 2020 07:29:33 +0100, Graeme
wrote:

In message , T i m
writes

OOI, do we think that the models shown on the CSE site are in any way
different to those (exact looking) sold via the likes of eBay or
Amazon etc? Not that CSE's prices aren't competitive etc?

I think they are identical, although I don't have two units from
different sources side by side to compare. Speaking to friends, some
have purchased via Amazon or eBay and some (like me) direct from CSE,
and all seem the same.

Thanks.

After looking around and starting to get distracted by feature creep,
I think I'm now resigned to go for the same as you and yer MR friends
and go for the SM 30/5 jobby, partly because of the price (bang for
buck), partly because your usage would be similar to mine (running
things that aren't 'fussy' about voltage), ease of voltage adjustment
and the compact size and light weight.

The strange thing is that with a digital display you can be inclined
to try to set the voltage exactly, say 12.00V when in many cases it
wouldn't actually matter if it was 10 or 15 (as you are driving a
voltage regulator in the first place). When I had the analogue
displayed meter you just turned it to 'about' 12V and you were happy
to leave it at that (very fast).

I'm comparing that with the 4 digit analogue PSU with the encoder
style digit-by-digit adjustment and just wondering if that might
become a bit tiresome in use?

Like if you want to go from 12 to 5V (I believe you have to):

Press the voltage knob
Turn it to select the units field (2)
Press the knob again to select that field
Turn it up to 5, (you now have 15V)
Press the knob again to enter that value
Turn it to select the 10's field (1)
Press the knob again to select that field
Turn it from 1 to 0 (now saying 5V)
Not sure if you have to press it to select 0 or that it times out to
0?

It's similar to setting some clocks.

On the simpler linear adjustment versions and assuming the 'Fine'
control knob is set in the middle of it's range.

Turn the 'Coarse' voltage knob down from 12 to 5V, or as near as you
can get with that control. If required, turn the 'Fine' voltage
control to get a more accurate value.

Cheers, T i m

In article ,
T i m wrote:
I have a couple of linear PSU's (Weir, both 30V-2A, 15V-4A) but they
are both old and are now non-functional / iffy and I was considering
something newer, lighter, smaller and with twin digital displays (on
the Weir's you have to switch between displaying V and A).

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

It's for general use, (temporarily) powering 5/12V things, charging
the odd battery and the like.

A 10A capacity might mean it can batter handle a 5A output, quieter
the better (some use small heatsinks and small fans) and ideally under
say £100?

I did look at kits (good to know you have the cct diagram) but that's
probably not best done with a SMPSU and linear stuff also seems to
require large heatsinks and heavy switching devices, all taking extra
time to source/ build (unless a complete kit with case / hardware
etc).

I bought one from CPC some time ago. Twin unit, and does +/- rails at the
push of a switch. Shows voltage and current from both at all times - 4
displays. Badged Circuit Specialists EU. Been very pleased with it. It
does 0-50v so useful for testing power amp PCBs.

It's neither small or light, though.

--
*Despite the cost of living, have you noticed how it remains so popular?*

Dave Plowman London SW
To e-mail, change noise into sound.

In message , T i m
writes

Turn the 'Coarse' voltage knob down from 12 to 5V, or as near as you
can get with that control. If required, turn the 'Fine' voltage
control to get a more accurate value.

For my fairly basic use, I just leave both the fine controls and the
amps at maximum, and use the coarse volts knob for control. The huge
advantage is the digital readout which shows both volts and amps
simultaneously, which is important for older motors. Just one example
is pre war permanent magnet motors. The magnets tend to degrade over
time, and consume more and more amps for the same performance, which
leads to overheating and damage to motor windings. Watching amps
consumed, and knowing the usual usage, is therefore important.
--
Graeme

On Wed, 16 Sep 2020 11:09:47 +0100, Graeme
wrote:

In message , T i m
writes

Turn the 'Coarse' voltage knob down from 12 to 5V, or as near as you
can get with that control. If required, turn the 'Fine' voltage
control to get a more accurate value.

For my fairly basic use, I just leave both the fine controls and the
amps at maximum, and use the coarse volts knob for control.

Ah, that makes sense for the current (compared with leaving the fine
current control in the middle), as it's a 'upper limit' and assuming
you may need the full output etc.

The huge
advantage is the digital readout which shows both volts and amps
simultaneously, which is important for older motors.

Understood. That said, if I was doing that same job with my Weir PSU's
with a single meter is I would set the voltage to something suitable,
say 12V and then switch it over to current and could then watch the
meter.

Only if I reached full current would the voltage drop.

Just one example
is pre war permanent magnet motors. The magnets tend to degrade over
time, and consume more and more amps for the same performance, which
leads to overheating and damage to motor windings.

Ahh.

Watching amps
consumed, and knowing the usual usage, is therefore important.

Understood. I was doing the exact same thing when testing the Arduino
based MR automated project with BIL [1].

We were both amazed at the differences in current pulled by his older
and newer locos.

Because there was no speed feedback in the project and the vast range
of speeds resulting from said motor efficiencies, rather than going
for the choice of running 'any' of his numerous locos, we selected a
sub-set that all had similar power requirements.

I can't think of any role where the noise from the PSU would be an
issue to me or the controls too coarse. (And I have used what looks
outwardly to be an identical model for a range of power and electronic
things and found it fine).

Cheers, T i m

[1] I actually still have our MR automation test rig here. 4m of
straight track with a bypass section in the middle. 4 digital IR
reflective sensors positioned by the track near the ends and a diode
connected 'dead' section each end of the track to prevent overruns.

Loco, pulls away from end (with inertia) to max speed (adjustable with
pot) to the 1st remote sensor then slows (with inertia) to a creep
speed to the second sensor when it stops.

The two points are set (using bridge drivers and a cap) and loco
drives back the other way and round the bypass and back onto the main
line, to the remote sensors. And it actually works. ;-)

Well when you say they are dead, its probably just capacitors, unless they
have been abused of course. My main problem with modern supplies are that
they are switch mode. Firstly unless very well designed they produce massis
of interference both down the mains, and radiating, and often there is a
residue actual on the DC as well. I'd be tempted to visit somewhere who
sells to Ham radio people, like Martin Lynch or Radioworld, or there are
several others, as they are more likely to know of gotchas on individual
supplies than than your average Ebay cheap Chinese box shifter.
Brian

--
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"T i m" wrote in message
...
I have a couple of linear PSU's (Weir, both 30V-2A, 15V-4A) but they
are both old and are now non-functional / iffy and I was considering
something newer, lighter, smaller and with twin digital displays (on
the Weir's you have to switch between displaying V and A).

There are loads over the normal suppliers but I wondered if anyone
here had got something reasonably recently that they could recommend?

It's for general use, (temporarily) powering 5/12V things, charging
the odd battery and the like.

A 10A capacity might mean it can batter handle a 5A output, quieter
the better (some use small heatsinks and small fans) and ideally under
say £100?

I did look at kits (good to know you have the cct diagram) but that's
probably not best done with a SMPSU and linear stuff also seems to
require large heatsinks and heavy switching devices, all taking extra
time to source/ build (unless a complete kit with case / hardware
etc).

Cheers, T i m

On Wed, 16 Sep 2020 11:02:51 +0100, "Dave Plowman (News)"
wrote:

snip

I bought one from CPC some time ago. Twin unit, and does +/- rails at the
push of a switch. Shows voltage and current from both at all times - 4
displays.

Are the controls linear or push, encode etc?

Badged Circuit Specialists EU.

They seem to be pretty popular. ;-)

Been very pleased with it. It
does 0-50v so useful for testing power amp PCBs.

I was torn re getting something with a 50V output (and at least 3A)
but think the prices start creeping up.

It's neither small or light, though.

That's not a dealbreaker, if it ticks enough of the other boxes
(price, speed / ease of use, reliability etc).

Cheers, T i m

On Wed, 16 Sep 2020 12:04:42 +0100, "Brian Gaff \(Sofa\)"
wrote:

Well when you say they are dead, its probably just capacitors, unless they
have been abused of course.

I think one is still working but not to full spec (it's been a while
since I've used it / them).

My main problem with modern supplies are that
they are switch mode. Firstly unless very well designed they produce massis
of interference both down the mains, and radiating, and often there is a
residue actual on the DC as well.

Ok, not sure that would affect a battery or model train. ;-)

I'd be tempted to visit somewhere who
sells to Ham radio people, like Martin Lynch or Radioworld, or there are
several others, as they are more likely to know of gotchas on individual
supplies than than your average Ebay cheap Chinese box shifter.

But may well be more expensive.? ;-(

I still have my 10A 13.8V linear 'Shack' PSU, a smaller adjustable
SMPSU 5-15V, 0-15A (current limiting) RC usage PSU and in the loft, a
*very* big and heavy 10A bench PSU that died (can't remember the
voltage range).

It's just that apart from the RC supply, none of the others are
working fully and whilst I can charge 12V batteries with the RC PSU,
it would have been handy to have 24V's worth of battery charging
(mobility scooters) and even higher voltages for a two wheeler
scooter.

Cheers, T i m

In article ,
T i m wrote:
On Wed, 16 Sep 2020 11:02:51 +0100, "Dave Plowman (News)"
wrote:

snip

I bought one from CPC some time ago. Twin unit, and does +/- rails at the
push of a switch. Shows voltage and current from both at all times - 4
displays.

Are the controls linear or push, encode etc?

Just knobs. ;-) Four which work independently when the two PS are
seperate, or just two of them when ganged.

Badged Circuit Specialists EU.

They seem to be pretty popular. ;-)

Been very pleased with it. It
does 0-50v so useful for testing power amp PCBs.

I was torn re getting something with a 50V output (and at least 3A)
but think the prices start creeping up.

It's neither small or light, though.

That's not a dealbreaker, if it ticks enough of the other boxes
(price, speed / ease of use, reliability etc).

It seems to do everything I want and hasn't annoyed me in any way. Which
is saying something.

I'm sure a SMPS one could be smaller, but I've built mine in on the side
of the workbench, so not taking up usable space. A bench top one would get
in the way at one point or another.

Cheers, T i m

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
To e-mail, change noise into sound.

In message
T i m wrote:

On Tue, 15 Sep 2020 21:39:56 +0100, John Bryan
wrote:

snip

Did you go for the linear one for a specific reason may I ask John and
if so, what OOI?


No I wanted one where the current limit was fully adjustable, which on my
model it is 0.001A to the max of 5.200A.

So that was a 'yes' then, the current limit thing. Bit isn't that
available on most 'current limiting' PSU's, even if they aren't so
easy to apply (without shorting the output) or as accurate to set?

I think most people use the current limit as a fuse or to limit the
current for charging a car battery, where I don't think you need so
much accuracy etc? It could be important when charging a very small
battery etc.

the adjustment of voltage or current is achieved by pressing in the
control knob to select the decade 10V.1V.0.1V,0.01V and turning the
encoder shaft to to desired value. Current setting likewise but
1A,0.1A,0.01A and 0.001A units.

I checked out the PSU you have on Youtube and saw that in action and I
was wondering how easy / fast it was to use in practice, compared with
a straight linear knob etc (the only type I've used).

If I use my Weir linear PSU as an example and charging a car battery.
If the battery was a reasonable size then I'd just wind the current to
max (assuming a 5A PSU), set the voltage to maybe 14V and connect up.
If it was as smaller capacity battery (say off a motorbike) I might
want to limit the current to 1A then I'd just turn the current knob up
or down till it reads 1A. If it's already fully charged it may only
take 1A (at 14V) for a few seconds in any case.

An example of where the selection method of the PSU you have was shown
on the Youtube video was where he set a very fine current limit to
drive a LED, saves having to bother with a series resistor etc.

I guess it might all boil down to how accurately you want to control
the voltage and current and how often you are changing it (along with
any other characteristics etc).

My Weir PSUs have a single analogue meter on the front (albeit quite a
big one) that you switch between volts and amps (triple reading scale
as it can go 0-15V and 0-30V, plus amps etc) and I've found it
sufficient for most of the stuff I've used it for so far. If I want
more voltage accuracy I just stick a DMM on the thing I'm powering.

The control knobs feel like they are wire would so probably quite
expensive. I just prefer the digital display and am not sure I need to
go down to that level of accuracy .01 V/A?

That's for bringing it to my attention though and I will consider it
further. ;-)

Cheers, T i m

I did not choose a linear power supply for any particular reason but as I
said the current limiting was more important for re-charging Ni-Cad
batteries in a couple of tools I have. Their chargers having died a few
years ago.

Both voltage and current setting are achieved using an encoder. When you
press the knob in the range digit flashes and whilst it remains in that
mode turning the knob adjusts the displayed value up or down.

Say you repeatedly pressed to set the 10mV range you can adjust the
voltage up or down throughout the output range 0 to 30 volts. It does take
quite a few revolutions to get the output up to 30volts from zero though.




--
John Bryan

On Wed, 16 Sep 2020 18:24:53 +0100, John Bryan
wrote:

snip


I did not choose a linear power supply for any particular reason but as I
said the current limiting was more important for re-charging Ni-Cad
batteries in a couple of tools I have.

OOI, don't most bench chargers have adjustable current limit?

Their chargers having died a few
years ago.

Like they do. ;-(

Both voltage and current setting are achieved using an encoder. When you
press the knob in the range digit flashes and whilst it remains in that
mode turning the knob adjusts the displayed value up or down.

Understood.

Say you repeatedly pressed to set the 10mV range you can adjust the
voltage up or down throughout the output range 0 to 30 volts. It does take
quite a few revolutions to get the output up to 30volts from zero though.

Ah, that's interesting and thanks for the clarification.

So if you set it on the units field you could wind it down from say 12
to 5 volts just by turning the knob (eg, it wouldn't just go from 12
to 10 and up to 19 and back down etc)?

If that was the case and based on the fact that most people would set
the volts in 'whole unit' increments, that would make it much more
useable IMHO).

Similar thing could happen with the current limit in that you could
have it on the .1 range and still have reasonable speed and
granularity?

Do you have to leave it to 'time out' on the individual digit for the
above to happen (eg, to stop it just cycling round that field or does
it never do that)?

Cheers, T i m

In message
T i m wrote:

On Wed, 16 Sep 2020 18:24:53 +0100, John Bryan
wrote:

snip


I did not choose a linear power supply for any particular reason but as I
said the current limiting was more important for re-charging Ni-Cad
batteries in a couple of tools I have.

OOI, don't most bench chargers have adjustable current limit?

Their chargers having died a few
years ago.

Like they do. ;-(

Both voltage and current setting are achieved using an encoder. When you
press the knob in the range digit flashes and whilst it remains in that
mode turning the knob adjusts the displayed value up or down.

Understood.

Say you repeatedly pressed to set the 10mV range you can adjust the
voltage up or down throughout the output range 0 to 30 volts. It does take
quite a few revolutions to get the output up to 30volts from zero though.

Ah, that's interesting and thanks for the clarification.

So if you set it on the units field you could wind it down from say 12
to 5 volts just by turning the knob (eg, it wouldn't just go from 12
to 10 and up to 19 and back down etc)?

The display would go from the initial 12, 11, 10, 9, 8, 7, 6, then 5.
Conversely going up 12, 13, 14,.....up to 30.


If that was the case and based on the fact that most people would set
the volts in 'whole unit' increments, that would make it much more
useable IMHO).

Similar thing could happen with the current limit in that you could
have it on the .1 range and still have reasonable speed and
granularity?
Yes and obviously on the 1 amp setting you only have five steps and on the
100mA setting 50steps.

Do you have to leave it to 'time out' on the individual digit for the
above to happen (eg, to stop it just cycling round that field or does
it never do that)?

Cheers, T i m


Yes you have to leave it to time out but it is only for 4-5 seconds.

The output display when setting mode increments/decrements the whole of
the voltage or current display.

So in your example when in the 100mV field, turning the control
anti-clockwise the display would show 11.90, then 11.80 and so on down to
5.10 then 5.00.
Left for 5 seconds the display stops flashing and the output is now set at
5.00 volts.

The display does not cycle round.
When at the minimum or maximum is gives a bleep as a warning.
The control can still be turned being but an encoder does not change the
output. ****
--
John Bryan

On Wed, 16 Sep 2020 23:50:17 +0100, John Bryan
wrote:

snip

So if you set it on the units field you could wind it down from say 12
to 5 volts just by turning the knob (eg, it wouldn't just go from 12
to 10 and up to 19 and back down etc)?

The display would go from the initial 12, 11, 10, 9, 8, 7, 6, then 5.
Conversely going up 12, 13, 14,.....up to 30.

Understood, thanks (once out of 'setting' mode?)


If that was the case and based on the fact that most people would set
the volts in 'whole unit' increments, that would make it much more
useable IMHO).

Similar thing could happen with the current limit in that you could
have it on the .1 range and still have reasonable speed and
granularity?

Yes and obviously on the 1 amp setting you only have five steps and on the
100mA setting 50steps.

Check.

Do you have to leave it to 'time out' on the individual digit for the
above to happen (eg, to stop it just cycling round that field or does
it never do that)?


Yes you have to leave it to time out but it is only for 4-5 seconds.

Check.

The output display when setting mode increments/decrements the whole of
the voltage or current display.

Is there any prior indication on what field you will be on when you
press the encoder again John or is it 'suck it and see' (press it and
see what flashes)?

So in your example when in the 100mV field, turning the control
anti-clockwise the display would show 11.90, then 11.80 and so on down to
5.10 then 5.00.

Check.

Left for 5 seconds the display stops flashing and the output is now set at
5.00 volts.

Ah, so, what happens to the output voltage between selections? Does it
stay at the last setting, follow the changes or disconnect till the
new voltage is selected etc?

The display does not cycle round.

Noted (and that might be just as well, depending on the output status
during changes etc).

When at the minimum or maximum is gives a bleep as a warning.

Ok.

The control can still be turned being but an encoder does not change the
output.

Understood.

Cheers, T i m

In message
T i m wrote:

On Wed, 16 Sep 2020 23:50:17 +0100, John Bryan
wrote:

snip

So if you set it on the units field you could wind it down from say 12
to 5 volts just by turning the knob (eg, it wouldn't just go from 12
to 10 and up to 19 and back down etc)?

The display would go from the initial 12, 11, 10, 9, 8, 7, 6, then 5.
Conversely going up 12, 13, 14,.....up to 30.

Understood, thanks (once out of 'setting' mode?)


If that was the case and based on the fact that most people would set
the volts in 'whole unit' increments, that would make it much more
useable IMHO).

Similar thing could happen with the current limit in that you could
have it on the .1 range and still have reasonable speed and
granularity?

Yes and obviously on the 1 amp setting you only have five steps and on the
100mA setting 50steps.

Check.

Do you have to leave it to 'time out' on the individual digit for the
above to happen (eg, to stop it just cycling round that field or does
it never do that)?


Yes you have to leave it to time out but it is only for 4-5 seconds.

Check.

The output display when setting mode increments/decrements the whole of
the voltage or current display.

Is there any prior indication on what field you will be on when you
press the encoder again John or is it 'suck it and see' (press it and
see what flashes)?

No.
I have just tested that and from power on the most significant field
flashes in either voltage or current setting mode. The least significant
field is only four quick pushes away.

If you miss it, just keep pressing as the display cycles through most to
least field and then back again least to most field, which seems a bit
wierd to me!

I have never given this a thought as it seemed to be intuitive to just
repeatedly press the control to get to the one needed.


So in your example when in the 100mV field, turning the control
anti-clockwise the display would show 11.90, then 11.80 and so on down to
5.10 then 5.00.

Check.

Left for 5 seconds the display stops flashing and the output is now set at
5.00 volts.

Ah, so, what happens to the output voltage between selections? Does it
stay at the last setting, follow the changes or disconnect till the
new voltage is selected etc?

The display does not cycle round.

Noted (and that might be just as well, depending on the output status
during changes etc).

When at the minimum or maximum is gives a bleep as a warning.

Ok.

The control can still be turned being but an encoder does not change the
output.

Understood.

Cheers, T i m


--
John Bryan

On Thu, 17 Sep 2020 19:21:06 +0100, John Bryan
wrote:

snip

Is there any prior indication on what field you will be on when you
press the encoder again John or is it 'suck it and see' (press it and
see what flashes)?

No.
I have just tested that and from power on the most significant field
flashes in either voltage or current setting mode.

Erm, so with current that would equate to whole amps and with voltage,
10's of volts or just volt units (given it goes to 30V)?

The least significant
field is only four quick pushes away.

So that would be from 10's of volts?

If you miss it, just keep pressing as the display cycles through most to
least field and then back again least to most field, which seems a bit
wierd to me!

And me ...?

I have never given this a thought as it seemed to be intuitive to just
repeatedly press the control to get to the one needed.

Yeah, I'm sure if it was in front of me I'd work it out easily but I'm
trying to ascertain how time consuming it might be if you were
changing stuff regularly and didn't need the accuracy / granularity.

So can I check on this please John. From power on, both voltage and
current flash the MSB and assuming you do nothing, will stop flashing
in ~5 seconds and will return to the last used values I understand
(say 12.000V, (or would it be only 12.00V?) and 3.000A current limit)
....

.... (Recap) If you then turn either knob then you will change values
in 10's of volts (or just volts?) and whole amps?

If you want to then say set it to 5.004V (for some reason g) you
first (just) turn the voltage knob (because it defaults to units?)
anticlock till it reads 5 in the units field then press the knob three
times and then ... (while it's still flashing or otherwise) turn it to
4?

Cheers, T i m

In message
T i m wrote:

On Thu, 17 Sep 2020 19:21:06 +0100, John Bryan
wrote:

snip

Is there any prior indication on what field you will be on when you
press the encoder again John or is it 'suck it and see' (press it and
see what flashes)?

No.
I have just tested that and from power on the most significant field
flashes in either voltage or current setting mode.

Erm, so with current that would equate to whole amps and with voltage,
10's of volts or just volt units (given it goes to 30V)?

When switched on the displays show the last settings of voltage and
current, after 5 seconds the displays indicate the measureded load
requirements.

The least significant
field is only four quick pushes away.

So that would be from 10's of volts?
Yes

If you miss it, just keep pressing as the display cycles through most to
least field and then back again least to most field, which seems a bit
wierd to me!

And me ...?

I have never given this a thought as it seemed to be intuitive to just
repeatedly press the control to get to the one needed.

Yeah, I'm sure if it was in front of me I'd work it out easily but I'm
trying to ascertain how time consuming it might be if you were
changing stuff regularly and didn't need the accuracy / granularity.

It does seem a little complicated but within a few minutes it will become
obvious as to the setting up.

So can I check on this please John. From power on, both voltage and
current flash the MSB and assuming you do nothing, will stop flashing
in ~5 seconds and will return to the last used values I understand
(say 12.000V, (or would it be only 12.00V?) and 3.000A current limit)
...

No. The displays show the last settings used and then revert to the
measured values. To change them you press the relevant control and set
your requirement.

... (Recap) If you then turn either knob then you will change values
in 10's of volts (or just volts?) and whole amps?

Yes but only after you have pressed the control knob.

If you want to then say set it to 5.004V (for some reason g) you
first (just) turn the voltage knob (because it defaults to units?)
anticlock till it reads 5 in the units field then press the knob three
times and then ... (while it's still flashing or otherwise) turn it to
4?
You cannot set it to 05.004V

To set it to 5.04V - it only has a 4 digit display so can only get to 10mV
Power on
Press the voltage control knob
The 10V digit will flash - Turn down to zero
Press the voltage control knob again. the unity volts flash
Rotate control up/down to set 5V
Press control knob twice to get to 10mV and rotate to set to 05.04V

Hope this a little clearer

Current setting is likewise.

Cheers, T i m


--
John Bryan

On Fri, 18 Sep 2020 00:17:23 +0100, John Bryan
wrote:

snip

Erm, so with current that would equate to whole amps and with voltage,
10's of volts or just volt units (given it goes to 30V)?

When switched on the displays show the last settings of voltage and
current, after 5 seconds the displays indicate the measureded load
requirements.

The least significant
field is only four quick pushes away.

So that would be from 10's of volts?
Yes

Ok.

snip

So can I check on this please John. From power on, both voltage and
current flash the MSB and assuming you do nothing, will stop flashing
in ~5 seconds and will return to the last used values I understand
(say 12.000V, (or would it be only 12.00V?) and 3.000A current limit)
...

No.

Oh?

The displays show the last settings used

Isn't that what I said or were you not saying no to that bit?

and then revert to the
measured values.

Which in case of the voltage and assuming it's not already current
limiting will be the same as the initial value and the current will be
the actually current being drawn (not the limit)? But the point was it
*will* be the last uses values, not some arbitrary values.

To change them you press the relevant control and set
your requirement.

Yes, I get that bit. ;-)

... (Recap) If you then turn either knob then you will change values
in 10's of volts (or just volts?) and whole amps?

Yes but only after you have pressed the control knob.

Eh? So the knobs don't work 'normally', only when in setting mode?

Turn on.
Display shows last used settings with the MSB flashing.
Allow 10 seconds.
Display show last voltage used and current amps drawn.
Turn either knob and you do or don't change the values 'live' John?

If you want to then say set it to 5.004V (for some reason g) you
first (just) turn the voltage knob (because it defaults to units?)
anticlock till it reads 5 in the units field then press the knob three
times and then ... (while it's still flashing or otherwise) turn it to
4?
You cannot set it to 05.004V

To set it to 5.04V - it only has a 4 digit display so can only get to 10mV

I wasn't sure if you regained that extra digit when only showing
single volts rather than 10's of volts. Ok, that makes it clearer.

Power on
Press the voltage control knob
The 10V digit will flash - Turn down to zero
Press the voltage control knob again. the unity volts flash
Rotate control up/down to set 5V
Press control knob twice to get to 10mV and rotate to set to 05.04V

Hope this a little clearer

Yes, that's sorta how I thought it worked, but I am now confused re
where you were saying that if you turn the voltage knob up or down
either side of 10V you will see 10, 9, 8, 9, 10, 11,12 etc?

Current setting is likewise.

Let's try a recap (I will get this pinned down). ;-)

1) Switch on

2a) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 1 (of the 12)
and 3 are flashing.
(I think I understand it to be this)

or

2b) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 12 and 3 are
flashing.
(not this?).

3) Leave for ~5 s and the PSU will provide the volts and current limit
values displayed.

4) Press the voltage button once and because it defaults to the first
(most significant) digit, that will flash, allowing you to set that
field ONLY. eg, if you keep rotating it clockwise from 1 it will go to
2 then 3 (then stop doing anything as the max voltage is 30 (and I
think you said it will beep)). Whilst it's still flashing, turning it
anticlock will see the display going from 3, 2, 1 to 0 and another
'end of range' beep. Leave the knob for ~5s and that digit will stop
flashing and that value will become the used value.

5) If you press the voltage knob again (once it's returned to steady)
you will 'still' be at the most significant field (so say the 1 of
12V) so you will be in the same position as in 4).

6) If whilst the display is flashing, you press the knob a second
time, the next (less significant) field will start to flash, so if it
was reading 12V, it will now be the 2. Then rotating the knob
clockwise will see the values going up to 9 (then beep ... or only
beep once you try to go *past* 9?) and anticlockwise the value going
back down to 0 (and then beep there or if you try to go past 0).

7) With the active voltage adjust units field left as the active one
(so 2 of 12V), and ~5s have passed, rotating the voltage knob will
increase or decrease the voltage in whole units up to 30 and down to
zero. (?)

8) With the display flashing, repeatedly pressing the knob will see
the flashing field move backwards and forwards between the two ends
(like ''Kit' the car on Night Rider). ;-)

Assuming I'm close now, I'm also interested to know at what point the
voltage (/ current) actually changes? eg, is it as you select it or
only when it's set?

Also to confirm the knobs *can* be used live as I believe you have
said previously across the full range and in whatever increments you
have last set (1V, 0.1V, 0.00A etc).

Thanks for your time John.

Cheers, T i m

In message
T i m wrote:

On Fri, 18 Sep 2020 00:17:23 +0100, John Bryan
wrote:

snip

Erm, so with current that would equate to whole amps and with voltage,
10's of volts or just volt units (given it goes to 30V)?

When switched on the displays show the last settings of voltage and
current, after 5 seconds the displays indicate the measureded load
requirements.

The least significant
field is only four quick pushes away.

So that would be from 10's of volts?
Yes

Ok.

snip

So can I check on this please John. From power on, both voltage and
current flash the MSB and assuming you do nothing, will stop flashing
in ~5 seconds and will return to the last used values I understand
(say 12.000V, (or would it be only 12.00V?) and 3.000A current limit)
...

No.

Oh?

The displays show the last settings used

Isn't that what I said or were you not saying no to that bit?

When powered up both displays show the users last settings but do not
flash. After a few seconds they display the supplied values.
CV led lit assuming not in current limit mode.

and then revert to the
measured values.

Which in case of the voltage and assuming it's not already current
limiting will be the same as the initial value and the current will be
the actually current being drawn (not the limit)? But the point was it
*will* be the last uses values, not some arbitrary values.
This is correct it will be the last user set values.
I do not know how long it retains these values as I have never left it
powered off more than few days.

To change them you press the relevant control and set
your requirement.

Yes, I get that bit. ;-)

... (Recap) If you then turn either knob then you will change values
in 10's of volts (or just volts?) and whole amps?

Yes but only after you have pressed the control knob.

Eh? So the knobs don't work 'normally', only when in setting mode?

Turn on.
Display shows last used settings with the MSB flashing.
Allow 10 seconds.
Display show last voltage used and current amps drawn.
Turn either knob and you do or don't change the values 'live' John?

If you want to then say set it to 5.004V (for some reason g) you
first (just) turn the voltage knob (because it defaults to units?)
anticlock till it reads 5 in the units field then press the knob three
times and then ... (while it's still flashing or otherwise) turn it to
4?
You cannot set it to 05.004V

To set it to 5.04V - it only has a 4 digit display so can only get to 10mV

I wasn't sure if you regained that extra digit when only showing
single volts rather than 10's of volts. Ok, that makes it clearer.

Power on
Press the voltage control knob
The 10V digit will flash - Turn down to zero
Press the voltage control knob again. the unity volts flash
Rotate control up/down to set 5V
Press control knob twice to get to 10mV and rotate to set to 05.04V

Hope this a little clearer

Yes, that's sorta how I thought it worked, but I am now confused re
where you were saying that if you turn the voltage knob up or down
either side of 10V you will see 10, 9, 8, 9, 10, 11,12 etc?

Current setting is likewise.

Let's try a recap (I will get this pinned down). ;-)

1) Switch on

2a) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 1 (of the 12)
and 3 are flashing.
(I think I understand it to be this)

or

2b) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 12 and 3 are
flashing.
(not this?).

3) Leave for ~5 s and the PSU will provide the volts and current limit
values displayed.

4) Press the voltage button once and because it defaults to the first
(most significant) digit, that will flash, allowing you to set that
field ONLY. eg, if you keep rotating it clockwise from 1 it will go to
2 then 3 (then stop doing anything as the max voltage is 30 (and I
think you said it will beep)). Whilst it's still flashing, turning it
anticlock will see the display going from 3, 2, 1 to 0 and another
'end of range' beep. Leave the knob for ~5s and that digit will stop
flashing and that value will become the used value.

5) If you press the voltage knob again (once it's returned to steady)
you will 'still' be at the most significant field (so say the 1 of
12V) so you will be in the same position as in 4).

6) If whilst the display is flashing, you press the knob a second
time, the next (less significant) field will start to flash, so if it
was reading 12V, it will now be the 2. Then rotating the knob
clockwise will see the values going up to 9 (then beep ... or only
beep once you try to go *past* 9?) and anticlockwise the value going
back down to 0 (and then beep there or if you try to go past 0).

7) With the active voltage adjust units field left as the active one
(so 2 of 12V), and ~5s have passed, rotating the voltage knob will
increase or decrease the voltage in whole units up to 30 and down to
zero. (?)

8) With the display flashing, repeatedly pressing the knob will see
the flashing field move backwards and forwards between the two ends
(like ''Kit' the car on Night Rider). ;-)

Assuming I'm close now, I'm also interested to know at what point the
voltage (/ current) actually changes? eg, is it as you select it or
only when it's set?

Also to confirm the knobs *can* be used live as I believe you have
said previously across the full range and in whatever increments you
have last set (1V, 0.1V, 0.00A etc).

Thanks for your time John.

Cheers, T i m

No problem you got me to try something I had never given a thought about
i.e. the digit cycling. Hope this has been of help.

--
John Bryan

In message
T i m wrote:

On Fri, 18 Sep 2020 00:17:23 +0100, John Bryan
wrote:

snip

Erm, so with current that would equate to whole amps and with voltage,
10's of volts or just volt units (given it goes to 30V)?

When switched on the displays show the last settings of voltage and
current, after 5 seconds the displays indicate the measureded load
requirements.

The least significant
field is only four quick pushes away.

So that would be from 10's of volts?
Yes

Ok.

snip

So can I check on this please John. From power on, both voltage and
current flash the MSB and assuming you do nothing, will stop flashing
in ~5 seconds and will return to the last used values I understand
(say 12.000V, (or would it be only 12.00V?) and 3.000A current limit)
...

No.

Oh?

The displays show the last settings used

Isn't that what I said or were you not saying no to that bit?

and then revert to the
measured values.

Which in case of the voltage and assuming it's not already current
limiting will be the same as the initial value and the current will be
the actually current being drawn (not the limit)? But the point was it
*will* be the last uses values, not some arbitrary values.

To change them you press the relevant control and set
your requirement.

Yes, I get that bit. ;-)

... (Recap) If you then turn either knob then you will change values
in 10's of volts (or just volts?) and whole amps?

Yes but only after you have pressed the control knob.

Eh? So the knobs don't work 'normally', only when in setting mode?
Oops missed this one
Yes you can turn the knobs until the cows come home and it will not change
anything. Only when the knob is pressed in and a digit is flashing.
I presume pressing the knob signals the control circuit and enables the
knob encoder to change something.

Turn on.
Display shows last used settings with the MSB flashing.
Allow 10 seconds.
Display show last voltage used and current amps drawn.
Turn either knob and you do or don't change the values 'live' John?

If you want to then say set it to 5.004V (for some reason g) you
first (just) turn the voltage knob (because it defaults to units?)
anticlock till it reads 5 in the units field then press the knob three
times and then ... (while it's still flashing or otherwise) turn it to
4?
You cannot set it to 05.004V

To set it to 5.04V - it only has a 4 digit display so can only get to 10mV

I wasn't sure if you regained that extra digit when only showing
single volts rather than 10's of volts. Ok, that makes it clearer.

Power on
Press the voltage control knob
The 10V digit will flash - Turn down to zero
Press the voltage control knob again. the unity volts flash
Rotate control up/down to set 5V
Press control knob twice to get to 10mV and rotate to set to 05.04V

Hope this a little clearer

Yes, that's sorta how I thought it worked, but I am now confused re
where you were saying that if you turn the voltage knob up or down
either side of 10V you will see 10, 9, 8, 9, 10, 11,12 etc?

Current setting is likewise.

Let's try a recap (I will get this pinned down). ;-)

1) Switch on

2a) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 1 (of the 12)
and 3 are flashing.
(I think I understand it to be this)

or

2b) At switch on and for ~5 seconds ... display shows last used
voltage and current limit values with the most significant field(s)
flashing. So if it was set to 12.00V and 3.000A CL, the 12 and 3 are
flashing.
(not this?).

3) Leave for ~5 s and the PSU will provide the volts and current limit
values displayed.

4) Press the voltage button once and because it defaults to the first
(most significant) digit, that will flash, allowing you to set that
field ONLY. eg, if you keep rotating it clockwise from 1 it will go to
2 then 3 (then stop doing anything as the max voltage is 30 (and I
think you said it will beep)). Whilst it's still flashing, turning it
anticlock will see the display going from 3, 2, 1 to 0 and another
'end of range' beep. Leave the knob for ~5s and that digit will stop
flashing and that value will become the used value.

5) If you press the voltage knob again (once it's returned to steady)
you will 'still' be at the most significant field (so say the 1 of
12V) so you will be in the same position as in 4).

6) If whilst the display is flashing, you press the knob a second
time, the next (less significant) field will start to flash, so if it
was reading 12V, it will now be the 2. Then rotating the knob
clockwise will see the values going up to 9 (then beep ... or only
beep once you try to go *past* 9?) and anticlockwise the value going
back down to 0 (and then beep there or if you try to go past 0).

7) With the active voltage adjust units field left as the active one
(so 2 of 12V), and ~5s have passed, rotating the voltage knob will
increase or decrease the voltage in whole units up to 30 and down to
zero. (?)

8) With the display flashing, repeatedly pressing the knob will see
the flashing field move backwards and forwards between the two ends
(like ''Kit' the car on Night Rider). ;-)

Assuming I'm close now, I'm also interested to know at what point the
voltage (/ current) actually changes? eg, is it as you select it or
only when it's set?

Also to confirm the knobs *can* be used live as I believe you have
said previously across the full range and in whatever increments you
have last set (1V, 0.1V, 0.00A etc).

Thanks for your time John.

Cheers, T i m



--
John Bryan

On Fri, 18 Sep 2020 18:22:13 +0100, John Bryan
wrote:

snip

When powered up both displays show the users last settings but do not
flash.

Ah, sorry.

After a few seconds they display the supplied values.
CV led lit assuming not in current limit mode.

Ok.

and then revert to the
measured values.

Which in case of the voltage and assuming it's not already current
limiting will be the same as the initial value and the current will be
the actually current being drawn (not the limit)? But the point was it
*will* be the last uses values, not some arbitrary values.

This is correct it will be the last user set values.

Ok good.

I do not know how long it retains these values as I have never left it
powered off more than few days.

I guess if they were held in some sort of NV RAM it could be
indefinitely. ;-)
snip

No problem you got me to try something I had never given a thought about
i.e. the digit cycling.

;-)

Hope this has been of help.

Yeah, I think so John, thanks. ;-)

Cheers, T i m

On Fri, 18 Sep 2020 18:26:25 +0100, John Bryan
wrote:

snip

Eh? So the knobs don't work 'normally', only when in setting mode?

Oops missed this one

Well, there were quite a few questions. ;-)

Yes you can turn the knobs until the cows come home and it will not change
anything. Only when the knob is pressed in and a digit is flashing.

Ah, got it.

I presume pressing the knob signals the control circuit and enables the
knob encoder to change something.

Yes, probably good if you were to nudge them round by mistake. [1]

Cheers, T i m

[1] Years ago I was having the physiotherapy on my back for a trapped
nerve and had a session of electro therapy, electrodes suck on my back
and hooked up to a machine causing my back muscles to contract and
release at a couple of second intervals.

Laying on my front, machine on a trolley by my head hands and me on my
elbows, left to 'turn the voltage level up, as / when you can handle
it' .. .

She left me set on level 3 of 10 and I'd slowly got it up up about 5
when, as I'd just got my hand on the level knob my elbow slipped off
the end of the bed and I span it round to 10!

Now, whilst I could just about cope with the pain, I initially
couldn't recover enough between bursts to get my hands back on the
machine to turn it down (but after a few goes I did). Now, if you had
to press the knob in fist, that wouldn't have happened. ;-(

In message
T i m wrote:

On Fri, 18 Sep 2020 18:26:25 +0100, John Bryan
wrote:

snip

Eh? So the knobs don't work 'normally', only when in setting mode?

Oops missed this one

Well, there were quite a few questions. ;-)

Yes you can turn the knobs until the cows come home and it will not change
anything. Only when the knob is pressed in and a digit is flashing.

Ah, got it.

I presume pressing the knob signals the control circuit and enables the
knob encoder to change something.

Yes, probably good if you were to nudge them round by mistake. [1]

Cheers, T i m

[1] Years ago I was having the physiotherapy on my back for a trapped
nerve and had a session of electro therapy, electrodes suck on my back
and hooked up to a machine causing my back muscles to contract and
release at a couple of second intervals.

Laying on my front, machine on a trolley by my head hands and me on my
elbows, left to 'turn the voltage level up, as / when you can handle
it' .. .

She left me set on level 3 of 10 and I'd slowly got it up up about 5
when, as I'd just got my hand on the level knob my elbow slipped off
the end of the bed and I span it round to 10!

Now, whilst I could just about cope with the pain, I initially
couldn't recover enough between bursts to get my hands back on the
machine to turn it down (but after a few goes I did). Now, if you had
to press the knob in fist, that wouldn't have happened. ;-(

Would have thought this should have been a stepped switch to prevent just
this. I take you survived this misfortune and are now worse for it.
I felt for you when I read your recollection.

I had to endure a bout of Physio terrorism and did ask to see their big
book of 1001 Ways To Inflict Pain (available in hardback)...
Ha Ha only joking

--
John Bryan

On Sat, 19 Sep 2020 19:43:09 +0100, John Bryan
wrote:

snip

She left me set on level 3 of 10 and I'd slowly got it up up about 5
when, as I'd just got my hand on the level knob my elbow slipped off
the end of the bed and I span it round to 10!

Now, whilst I could just about cope with the pain, I initially
couldn't recover enough between bursts to get my hands back on the
machine to turn it down (but after a few goes I did). Now, if you had
to press the knob in fist, that wouldn't have happened. ;-(

Would have thought this should have been a stepped switch to prevent just
this.

It was actually weighted (like a HiFi volume knob), so once it started
....

I take you survived this misfortune and are now worse for it.

Yes. It was just *very* uncomfortable at the time (as in
electro-induced muscular cramping) but it died went off pretty
quickly. ;-)

I felt for you when I read your recollection.

Thanks. It was definitely 'a moment' I would have preferred not to
experience but did make for a good story.

I had to endure a bout of Physio terrorism and did ask to see their big
book of 1001 Ways To Inflict Pain (available in hardback)...

'This will probably hurt you more than it hurts me ...' ;-)

Ha Ha only joking

;-)

I can't remember if the 'treatment' helped but I think I only had 2 or
3 sessions (BUPA).

Cheers, T i m