A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

Details in Drop Box :-

dial gauge.txt
Circuit diagram.jpg
Synchro Sensor.jpg
Clocking Workpiece.jpg


Jim

In article ,
says...

A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

These are some pretty big files.

http://www.metalworking.com/DropBox/dial_gauge.txt
http://www.metalworking.com/DropBox/Circuit_diagram.jpg
http://www.metalworking.com/DropBox/Synchro_Sensor.jpg
http://www.metalworking.com/DropBox/Clocking_Workpiece.jpg

DoN mode on
It would help if you made the titles of the dropbox files
start with the same prefix, something like JimPent_dialgage, etc,
so that they all show up in a block.
DoN off

Cool project. It looks like the heart of the matter is a
syncro selsyn trasmitter, right? Is this off-the shelf, or
was it surplus?

Recently having gotten deep into my Federal electronic readout
I appreciate how interesting this stuff is. In that case they
ran the phase senstive detector with a resonant circuit front
end - and they missed soldering one of the fine wires inside
the inductor to the lead-out pin. It worked just fine for
about ten years before the connection went open and the thing
quit working.

Jim


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please reply to:
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wrote in message
...
A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

Details in Drop Box :-

dial gauge.txt
Circuit diagram.jpg
Synchro Sensor.jpg
Clocking Workpiece.jpg


Jim

Many years ago I started building a brute force digital dial indicator
by calculating XY coordinates for a circular pattern with 100 equally
spaced holes. Then I drilled them using a small mill, dialing in each
coordinate. The material was a disk made of engraving plastic stock.
My intent was to make an optical reader using up/down counters and
attach it to a normal dial indicator stem in place of the hand.

Never finished it , but I still have the disk in my tool box. Inertia
was a bitch ; )

On 25 Jun 2005 08:34:03 -0700, jim rozen
wrote:

In article ,
says...

A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

These are some pretty big files.

http://www.metalworking.com/DropBox/dial_gauge.txt
http://www.metalworking.com/DropBox/Circuit_diagram.jpg
http://www.metalworking.com/DropBox/Synchro_Sensor.jpg
http://www.metalworking.com/DropBox/Clocking_Workpiece.jpg

DoN mode on
It would help if you made the titles of the dropbox files
start with the same prefix, something like JimPent_dialgage, etc,
so that they all show up in a block.
DoN off

Cool project. It looks like the heart of the matter is a
syncro selsyn trasmitter, right? Is this off-the shelf, or
was it surplus?

Recently having gotten deep into my Federal electronic readout
I appreciate how interesting this stuff is. In that case they
ran the phase senstive detector with a resonant circuit front
end - and they missed soldering one of the fine wires inside
the inductor to the lead-out pin. It worked just fine for
about ten years before the connection went open and the thing
quit working.

Jim

The synchro is a surplus size size 08 control transmitter which
is a pretty common item in old aircraft instruments.

Sorry about the messy post.

jim

On Sat, 25 Jun 2005 14:14:35 +0100, wrote:

A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

Details in Drop Box :-

dial gauge.txt
Circuit diagram.jpg
Synchro Sensor.jpg
Clocking Workpiece.jpg


Jim

Jim,
Nice job!
I love the concept.

Any idea on sources for the synchro transmitter? Where the ones you
used 400Hz units? I have several, but they are a much larger and are
120V 400Hz units.

Thanks for posting this stuff!

AL A.

On Sat, 25 Jun 2005 21:15:05 -0400, Al A.
wrote:

On Sat, 25 Jun 2005 14:14:35 +0100, wrote:

A bit off topic but could be useful for some measurement problems.

Home brew, remote readout, lever type dial gauge
+-0.0025" & +-0.025" Full scale
Also usable with linear inductive sensors.

Details in Drop Box :-

dial gauge.txt
Circuit diagram.jpg
Synchro Sensor.jpg
Clocking Workpiece.jpg


Jim

Jim,
Nice job!
I love the concept.

Any idea on sources for the synchro transmitter? Where the ones you
used 400Hz units? I have several, but they are a much larger and are
120V 400Hz units.

Thanks for posting this stuff!

AL A.


The unit I used is a 2608CX4 rated as a 26v 400Hz control
transmitter rescued from old aircraft bits. Pretty well any surplus
outfit stocking bits of aircraft or military instruments should have
something suitable. Where are you? Perhaps someone with local
knowledge can provide a few pointers.

The circuit is not fussy on the type of synchro - the 2608CX4
is about the most demanding type. This 26v 400Hz transmitter loads the
555 more heavily than practically any other type. Synchro receivers,
resolvers, control transformers, 60 or 400Hz, 26v or 120v should all
be OK. The changes needed should be limited to choice of damping R and
overall gain.

One other variable is the operating frequency - 1KHz was
chosen as higher than 400Hz to reduce the load on the 555 but still
low enough for the secondary waveform to be a pretty clean squarewave.
1KHz should still be OK for 60Hz synchros. It could be increased if
the synchro you find loads the 555 too heavily.

Jim

In article , jim rozen says...


http://www.metalworking.com/DropBox/Circuit_diagram.jpg

Hmm. Nice phase detector.

What's the 50K pot doing at the last (meter) stage?

Jim


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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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On 26 Jun 2005 13:40:25 -0700, jim rozen
wrote:

In article , jim rozen says...


http://www.metalworking.com/DropBox/Circuit_diagram.jpg

Hmm. Nice phase detector.

What's the 50K pot doing at the last (meter) stage?

Jim

Wide range Zero set (about 3x full scale) - it performs the same
function as rotating the outer dial on a mechanical dial gauge. Much
more convenient because it does it without mechanically disturbing the
measuring head.

It also backs off the zero offset error of the earlier
stages.

Jim

In article ,
says...

What's the 50K pot doing at the last (meter) stage?

Wide range Zero set (about 3x full scale) - it performs the same
function as rotating the outer dial on a mechanical dial gauge. Much
more convenient because it does it without mechanically disturbing the
measuring head.

Ah, got it. The current throught the 680K is summing in with
the real measurement current. The layout on the diagram had me
stumped there for a bit - it took me a while to realize you
were deriving a driven 'ground' on that middle buss there.

Jim


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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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