wring out a lot of wire

I pulled to the old servo drives out of my Matsurra bed mill and got all the wire run cables separated as much as possible. Most of the I/O cables have less than ten conductors and you can deduce what they are for by where the cable run goes.

I have two fifty conductor cables that go to the operator panel. I'm guessing fifty inputs on the operator panel so there are a great many more wires than used. I have no manual for this machine and these wires aren't numbered. Looks like a REAL MESS to figure out the function of each wire.

Each input is pretty simple, if it is made it conducts voltage. But doing this many at once becomes a snow storm. Any suggestions on best approach?

Karl

Reply to
Karl Townsend
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That's a very tough job. I would first invest a lot of effort into finding a manual and schematic.

i
Reply to
Ignoramus24898

Till then, ground your ohmmeter and determine which of those 50 are 'returns'. That will cut down on your work *a lot*.

You could discover that you're challenge is *only* 30 connections.

--Winston

Reply to
Winston

Usually the connector is numbered on face or rear or face AND rear. Sometimes you can come up with a numbering scheme by looking up the connector in a catalog. Very few manufacturers used proprietary connectors, they may not be common, but somebody had to have made them. Anything beyond just a few pairs of wires will have some kind of numbering scheme or the techs wouldn't be able put the cables together correctly in the first place or service the thing afterwards. Usually there's a color code on the wiring, too. I'll second the other poster about making an extreme effort to get some kind of service data. Somebody had to fix the things! Otherwise, you're in for a long session with a buzzer and battery.

Stan

Reply to
stans4

I would group a lot of resistors and tie one end of all of the to ground to ground. Use in multiples of 10, like 10, 100, 1k, 10k, 100k,

1M, 10M ohms to make it obvious which wire is which. Then probe the wires at the other end. In seven passes you can identify the entire cable.
Reply to
Michael A. Terrell

Matsuura is still in business. Call them, call dealers, bribe dealers etc.

i
Reply to
Ignoramus24898

50 conductor sounds like telephone cable. Are the wires stranded or solid? Are they pairs of wires twisted together? If twisted together, then you have pairs already and only have 25 pairs to deal with.

Paul

Reply to
co_farmer

Didn't he say all all he had left was the wire? That everything else had been removed, and the wires were unmarked?

Reply to
Michael A. Terrell

There is also 50 conductor (and larger) control cable. Telephone wire is typically solid 24 or 26 AWG that doesn't hold up well with vibration.

Reply to
Michael A. Terrell

I just checked this. On first run, nothing grounded, but I don't have the dead 6M fanuc computer here, its at the kid's place. Maybe this cable was grounded on one end at the computer for all the extra conductors. You're right, if I could eliminate half, the job would be simpler.

Reply to
Karl Townsend

This machine has waited YEARS for a refit, hoping for manuals. No joy, and we've tried A LOT. Your suggestion for different resistors has merit. But I'm still hoping for some kind of suggestion to test several at a time for voltage.

Karl

Reply to
Karl Townsend

I haven't cut the fanuc connector off yet, so i don't know what I'll see inside. Surely 1/2 of these conductors are grounded. best suggestion so far is to focus on figuring this out first.

Next, I'm thinking 50 lights on a terminal strip or??? Could use a good idea here.

Karl

Reply to
Karl Townsend

It has saved me weeks worth of work ringing out large bundles of audio cables in school intercoms.

Reply to
Michael A. Terrell

I use one of these...

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I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Reply to
Gunner Asch

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I came up with the resistor method when I had to ring out about 70 pairs in a school building, and the ends were over 1/4 mile apart. Some kids had vandalized the intercom by breaking into a 24" * 24" junction box. They ripped out all the wire nuts, then removed all the little jewlwery store type paper tags my competiton used on their jobs. Only

55 pairs from the office were used. Some were duplicate callback lines, and others were spares. A telephone type tracer would have required me to walk over 35 miles to locate each half of each run. because the campus was huge.

I bought one of these, but I haven't used it yet:

Reply to
Michael A. Terrell

On 9/26/2010 8:55 PM, Karl Townsend wrote: (...)

Does your ohmmeter have a 'beep' continuity mode?

(This goes a lot faster than my explanation implies.)

Start by shorting the two probes together to confirm the meter will beep properly.

Place one probe on pin 1 and move the other probe to pin 2 - 50 in sequence. Record all beeps. Move your probe from pin 1 to pin 2 and repeat your scan with your other probe.

If a pin beeps to any other pin, write that down. 'Pin 5 to pin 32' for example.

Eventually you will find a pin that beeps to a lot of other pins. (Often, many of the even - numbered pins or odd - numbered pins.) If these pins also beep to a ground point on the control panel, you have good evidence to support the theory that you found your ground connections.

Confirm this by switching to normal 'ohms' mode and check the 'beeping' connections once more. You should see that there is no difference in resistance between 'shorted probes' and your suspected connections. Remove any connection from your list that appears to exceed that resistance by say 0.7 ohm or more.

Example: With probes shorted together, you see that the meter reads 0.2 ohm. All the valid connections will read no more than say 0.9 ohm. (Practically speaking, your valid readings should also be in the 0.2 ohm - 0.5 ohm range).

A pin reading higher resistance should be dropped from your list (unless it is just a dirty connection that you can polish and bring under 0.9 ohm).

Use alligator clips to connect your beeping ohmmeter to your ground connection and hold the other probe in sequence to each of the pins that did not beep.

Press each button on the control panel till you hear your meter beep. Write down the pin number and button logo.

You can run this inspection in about 1% of the time it would take to build your terminal strip.

That is how I do it.

--Winston

Reply to
Winston

I don't quite understand the scope of this problem from your description. Do you need to reconstruct the connectivity, the functionality, or both?

When I check a cable for opens or shorts I sketch each exposed pin or socket face and label the pins with their number or letter, which on Mil circular connectors may be visible on the back of the insert after removing the backshell. With the shell off look for any Y splices, resistors, diodes etc within it. I draw a box or circle for each pin and fill in the unused ones.

The sketch makes keeping track of progress -much- easier.

Then I clamp or weight the connectors side by side facing me, tilted up so I can read any pin numbering and rotated to match the sketch. This leaves both hands free to hold the meter probes. If the probe is too big to fit into a socket I clip on one of the safety pins from my key ring.

Make a table listing all the pins in one connector, preferably the largest. Winston described how to buzz the wires out efficiently. If you didn't find splices and the number of wires is the same on both ends you can assume the first hit is the only one, though it's easy to wipe quickly across the rest of the connector. Record each hit in the table, like J22-5 --- J17-19.

Also mark all no connect pins, J22-8 -- nc.

When done, visually check that there's a wire in the connectors for each one in the table. This should catch any pin you missed or a splice that was covered up.

If you write the table in a spreadsheet you can expand it with the connections you find in the boxes and add signal names as you determine them.

The method that uses resistors requires extra connectors and pins. It works well for production where you have spare parts and recover the overhead of making the test connector in shorter test times and less skilled operators. I've never bothered with it for a few cables where it's easy to wipe the probe quickly listening for a beep, then localize it. For most newly made cables opens are far more likely than shorts so I just jumper pairs of pins together on both ends so a single continuity check will zigzag through all of the wires.

jsw

Reply to
Jim Wilkins

The fastest way to match-up ends of wires in a cable is a binary search. Where fastest means the least number of tests. The number of tests required is the number of bits needed to represent the number of wires. E.g. 64 wires would require 6 tests. This is especially efficient where each test means traveling some distance between the ends of the wires. I used it where I had a bunch of unmarked wires coming into a fuse panel, the other ends of which went all over the house. Each test involved traveling the house, testing each end.

A binary search involves dividing the wires into 2 groups for each test, then redividing them for the next test. When you're done, each wire has been in a unique collection of groups. For example, say you have 8 wires, arbitrarily numbered 1 through 8. For the 1st test, wires 1 - 4 are tied together (5-8 are loose). In the next test 1-2,5-6 are (all) tied & the 3rd test 1,3,5,7. For each test, the tied-together wires are rung to each of the loose wires on the other end. So, if a other-end wire rung to groups 1 & 3, it would be wire 3 (1-4, not 1-2, 1 or 3).

I could be more explicit, but you get the idea. If you number and group the wires right, the ring-ing groups are the binary number of the wire.

HTH, Bob

BTW - it's "ringing out" cables, from the use a buzzer/bell to test continuity.

Reply to
Bob Engelhardt

Oh, wait ... your cables have connectors on both ends, right? In that case, tieing ends together is not practical and you can "never mind" what I said.

Bob

Reply to
Bob Engelhardt

The suggestions you have received here are all pretty good. I would add, however, that you ought to "just do it." These kinds of jobs, while tedious, are often easier than you think. Just dive in, and in an hour, or a few hours, you'll be done and can move on.

That said, I remember reading, in the early 80s about a Cray supercomputer that contained thirty MILES of twisted pair 30 gauge wire wrap wire, all the same color. Talk about yer nightmares.

Reply to
rangerssuck

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