Hi,

I just got an offer for Chinese DROs (to fit onto a mill or a lathe),
that are quite cheap. I _would_ prefer Heidenhain, Sony or Mitutoyo, but
not my wallet!
These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I do have a Tek TDS waiting for some waves to sample, a programmer for
uCs, a laptop willing to cycle through some C-code and the knowledge to
put all the things together ...

Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

Nick Müller wrote:
Hi,

I just got an offer for Chinese DROs (to fit onto a mill or a lathe),
that are quite cheap. I _would_ prefer Heidenhain, Sony or Mitutoyo, but
not my wallet!
These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I do have a Tek TDS waiting for some waves to sample, a programmer for
uCs, a laptop willing to cycle through some C-code and the knowledge to
put all the things together ...

Nick
..
Nick, is this an offer that OTHERS might take advantage of?
If so, can ya share the info?
TIA
Bill

BillP wrote:

Nick, is this an offer that OTHERS might take advantage of?

I don't know.


If so, can ya share the info?

What do you want to know?
I only know, that there is a documentation about the protocol of the
Chinese scales and that there must be a way to convert it to V24 AKA
RS232. That's what the uC is for. Also I know, that I have done
something like this before. I further know, that this would not be my
first C-program.
I would not be to declined to make the info/code/etc PD.

If I would be a cop, I would say: "I ask the questions!" :-)


So anybody knows something about accuracy?


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

Nick Müller wrote:

BillP wrote:

Nick, is this an offer that OTHERS might take advantage of?

I don't know.

If so, can ya share the info?

What do you want to know?
I only know, that there is a documentation about the protocol of the
Chinese scales and that there must be a way to convert it to V24 AKA
RS232. That's what the uC is for. Also I know, that I have done
something like this before. I further know, that this would not be my
first C-program.
I would not be to declined to make the info/code/etc PD.

If I would be a cop, I would say: "I ask the questions!" :-)

So anybody knows something about accuracy?

Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

You might want to look at: http://www.shumatech.com/ before reinventing
the wheel.

Pete C.

I just got an offer for Chinese DROs (to fit onto a mill or a lathe),

that are quite cheap. I _would_ prefer Heidenhain, Sony or Mitutoyo,
but
not my wallet!
These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I bought Chinese DRO's as shown in:
http://www.shumatech.com/support/chinese_scales.htm
As far as I can tell the accuracy is OK but I have had a lot of trouble
with the scales losing synchronization with the readout due to the
flimsy nature of the electrical connection. When this happens you must
take out the batteries and leave them out for 1 minute, then replace.
The battery covers and the contacts are very poorly made and have given
me much trouble.
Engineman

Pete C. wrote:

You might want to look at: http://www.shumatech.com/ before reinventing
the wheel.

Thanks, I know that. But I don't want a dedicated board with uC +
display for that. Just a uC for the conversion DRO - V24.

Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

wrote:

As far as I can tell the accuracy is OK

In numbers? :-)


... but I have had a lot of trouble with the scales losing synchronization
with the readout due to the flimsy nature of the electrical connection.
When this happens you must take out the batteries and leave them out for 1
minute, then replace.

Good to know! Do you have the shumatech board or just his "dongles"?
When out of sync, was the display of the DROs confused, or "just" the
box doing the processing?
OK, the connectors will be a problem (I've read the articles), but I
guess that can be done mechanicaly healthy.
So, are you sure that it was only a mechanical problem?


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

As far as I can tell the accuracy is OK but I have had a lot of trouble
with the scales losing synchronization with the readout due to the
flimsy nature of the electrical connection...


You really need to solder the leads (or a header) directly to the board, don't
use the slide-in connectors. I used the 4 pin header listed in the Shumatech
optional list, but you could just as easily solder the wires right straight to
the board.

DT

On Sat, 03 Sep 2005 14:05:14 GMT, "JimEvans"
wrote:

Those Chinese units use magnetic scales ( like calipers) and have a number
of issues- they are very subject to any liquid contamination, the
connections are poor and the display uses LED's. The Shumatech is a good
way to go if you can source some decent scales and do your own display from
pieces. There is a good optical scale unit at a reasonable price if you are
looking for a turnkey system- they compare to to Mitutoyo, Heidenhahn ets
for quality and features , but much lower cost- go to
http://forums.delphiforums.com/MadeinUSA/start
Actually, the chinese scales use capacitance, not magnetism, to read
the scale. I suppose this is why they won't work when wet. However,
the Mitutoyo water resistant calipers use inductance as the measuring
method.
ERS
"Nick Müller" wrote in message
. ..
Hi,

I just got an offer for Chinese DROs (to fit onto a mill or a lathe),
that are quite cheap. I _would_ prefer Heidenhain, Sony or Mitutoyo, but
not my wallet!
These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I do have a Tek TDS waiting for some waves to sample, a programmer for
uCs, a laptop willing to cycle through some C-code and the knowledge to
put all the things together ...

Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

wrote:

but I have had a lot of trouble with the scales losing synchronization
with the readout due to the flimsy nature of the electrical connection.
When this happens you must take out the batteries and leave them out for 1
minute, then replace.

I just came across this text. It might help you:

"Anyway, among other things, it was discovered that, if the scales were
left connected to the DRO-350 when its power supply was unplugged, the
DRO-350 would drain the batteries in the scales. There was then a
procedure that had to be followed to get the scales to work correctly
again (remove the battery, leave it out for a minute, put in a new
battery, bury a dead cat under the big oak tree...). And on it went."

The solution is to leave out the batteries.


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

The best prices for optical scales are offered at the ShumaTech Yahoo
user group at http://groups.yahoo.com/group/ShumaTech/. They have been
tested by the users of the displays.

Regards,

Tim
LMSC
877-376-4373


On Sat, 03 Sep 2005 14:05:14 GMT, "JimEvans"
wrote:

Those Chinese units use magnetic scales ( like calipers) and have a number
of issues- they are very subject to any liquid contamination, the
connections are poor and the display uses LED's. The Shumatech is a good
way to go if you can source some decent scales and do your own display from
pieces. There is a good optical scale unit at a reasonable price if you are
looking for a turnkey system- they compare to to Mitutoyo, Heidenhahn ets
for quality and features , but much lower cost- go to
http://forums.delphiforums.com/MadeinUSA/start
"Nick Müller" wrote in message
. ..
Hi,

I just got an offer for Chinese DROs (to fit onto a mill or a lathe),
that are quite cheap. I _would_ prefer Heidenhain, Sony or Mitutoyo, but
not my wallet!
These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I do have a Tek TDS waiting for some waves to sample, a programmer for
uCs, a laptop willing to cycle through some C-code and the knowledge to
put all the things together ...

Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

LMSC wrote:

The best prices for optical scales are offered at the ShumaTech Yahoo

And what is the price range?
Also, I hate to subscribe to Yahoo.

What I have found here is abot 5..10 times the price of the Chinese
scales.


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de

Nick Müller wrote:

These cheapos seem to have a resolution of 1/100mm, but what's their
accuracy?

I got the answer of the dealer now:
He claims +/- 0.03mm on a 300mm scale?!

A Mitutoyo caliper, 300mm long, has +/- 0.04mm. Now would anyone trust
the +/-0.03 of the Chinese crapmanship ... er ... craftmanship?

Nick

--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de