Cable detached from controller to step motor

[Unique2022]

I have a milling machine which is 30 years old, and has a electronic divider and step motor.

The cable from the step motor to the electronic divider has become detached by cable in between, and I don't know have any diagrams of the wiring how can this be attached, is there possibility of getting new cables?

The other end of the cables from step motor and electronic divider have become detached, these meet in the middle as shown in the photos.

Much appreciate any solution.

 

[ddmckee54]

It looks to me like the plugs are damaged. All you should have to do is replace the plugs, and you should be good to go. The plugs look to be to be a standard 4 pin plug, you should be able to get replacement plugs and repair these cables in place.

 

[Unique2022]

Thanks for the response, it is an old machine with no electrical diagrams available, what would be the best way to find out the color to pin number connections for the two attachments.

 

[ddmckee54]

After taking a GOOD look at the Plugs Detached picture I believe I see your delemma. I think what I'm looking at is a set of male female 4 pin M12 connectors, that's what the Plugs Detached photo suggests to me. I'm a little confused by the photo showing the tag on the control box though, as that connector is definitely NOT a 4 pin connector. That connector is not part of this problem is it?

It looks like the female plug has broken apart and part of it is still in the male plug. What you are seeing in the close up of plug picture is the remainder of the solder connections that are sticking out on the Plugs Detached picture. The female plug is the silver plug, it will have the socket connections, and the other plug with the pin connections is the male plug. There's still a broken section in the male plug by the way, just unscrew silver collar and it will pull out. When this comes out you will be able to read the pin numbers on the end of the plug. These look like standard M12 four pin plugs, but without having them in my hands I can't be sure.

Those plugs will dis-assemble into several parts. You can loosen the screws on the cable clamp and the clamp will unthread off the body of the plug. There might be a screw, or screws, on the side of the main body of the plug that you'll need to take out. I can see a screw in the male plug so I assume there will be one in the female plug also. If we're lucky you will then be able to hold the body and push on the cable and the rest of the guts of the plug will come out. If we're REALLY lucky the wires will still be connected to the remainder of the sockets and you'll be able to read the pin numbers on the wire end. The pin numbers will be molded into the plastic, get out your magnifying glass because they will be small.

The next steps will be determined by how lucky you are up to this point. I looks like 2 differnet types of cable were used to wire these plugs so the color code in one plug may not match the color code in the other. The reason we NEED the pin numbers is that they WILL match up on both plugs. If you don't get lucky then we'll have to dig a little deeper into the controller. To quote Dirty Harry, "Ya feelin' lucky Punk?"

Worst case, we have to figure out how your stepper is supposed to be connected and then hook back it up that way. I tried Googling the model number of your controller and had no luck, the good new is that Epitaux Electonics still exists in Switzerland.

Don

 

[Unique2022]

Yes your right the connector on the controller is not the issue, this has 10 pin, and has two cables in one, on the clamp.

The other end of one of the cables (as shown on video) the black cable, is the male end, and the other end of the cable from step motor both connect together. These are disconnected.

I can see the numbers on the female end engraved, on the case 1-4. With the pins from the male end stuck inside.

The male end where the wires are colored, this is the issue since the pins are removed, and there is no obvious engraving of number on outside.

Is it possible to deduce the color to pin number connection using a multimeter and polarity.

 

[stanstocker]

It's not a promise, but it looks like only pins 1, 2, and 3 in the connector were used. It appears that the broken ends of the wires down in the connector shell are sitting in a triangular pattern that could be matched up to the connector to get the pin to wire color sorted out. The photo looking down into the shell is out of focus unfortunately, but maybe yellow to pin 1, red to pin 2, and idontknowmaybeblack to 3. Not sexy, but with no wiring data for the machine you sometimes have to do thing the dumb way

Good luck!
Stan

 

[ddmckee54]

OK, this is what I'm seeing in the pictures and what I'm understanding from you.

You have a grey 4 conductor cable that is connected to your stepper motor. I don't know a color code even exists for rebuilding that connector - but we can figure it out. The first thing we'll need to do is a little surgery on the existing connectors. We need to find out if the color code for the conductors of the grey cable is the same black cable connected to the other plug. Even if they aren't the same color code, this in no big deal, we will be able to figure this out.

Time to disassemble Johnny 5:
The male and female connectors screw together, so we need to start taking them apart.
1) Loosen and remove the silver ring from the grey plug. That silver ring is actually the locking ring that holds the female plug into the male plug.
2) p
Loosen and remove the screws holding the cable clamps on the end of the connectors. You'll need to do this to both the silver plug and the dark grey plug. Once you have the clamps removed you can unscrew that part of the plug from the rest of the plug body.

Edit : Disregard this post!!! This is 2nd time I been editing this and my hands twitched screwing it up. What you see is the result of the 1st time I twitched, and loaded the reply while I was still working on it. The 2nd time I was almost done with the reply when I lost all my work. I'm going to put this reply together off-line and get back to you.

 

[ddmckee54]

OK, Before we were so rudely interrupted, this is what I'm seeing in the pictures and what I'm understanding from you. You've got two plugs, a silver plug and one that I'm going to call grey. The silver plug is the female plug and is currently in 2 parts. A grey cable is attached to one part of the silver plug, while the other part is still attached to the grey plug. The grey plug is the male plug, and has a black cable attached to it.

You have a grey 4 conductor cable that is connected to your stepper motor, and a black cable that connects to your controller. I don't know if a color code even exists for rebuilding the connections through those plugs - but we can figure it out. The first thing we'll need to do is a little surgery on the existing connectors. We need to find out if the color code for the conductors of the grey cable is the same as the color code for the black cable connected to the other plug. Even if they aren't the same color code, this in no big deal, we will be able to figure this out. To do this we need to trace out the connections between the stepper motor and the controller. We may wind up opening every plug between the stepper and the controller, but when we are done we will know what wire connects to what pin in each connector - at least for this stepper. This is what I've done for a living for the last 40 years, ain't it fun? On Monday I'll CAD up a simple sketch of the connections between the controller and the stepper motor. There will be some of blanks that we'll need to fill in before you can actually put things back together, but that's just a matter of following wires.

The plugs themselves consist of several parts that screw together. The male plug consists of a strain relief assembly, the main body shell, and the pin assembly. The female plug consists of a strain relief assembly, the main body shell, and the socket assembly with locking ring. This socket assembly and locking ring are the silver parts that are still attached to the grey plug. We need to open these plugs up to look at the color code for the cables and see if the match. If they match, we're golden, if not - well we'll burn that bridge when we get to it.

The male and female connectors screw together, so we need to start taking them apart. Time to disassemble Johnny 5:
1) Loosen and remove the silver ring from the grey plug. That silver ring is actually the locking ring that holds the female plug into the male plug.
2) Pull the socket assembly for the silver plug out of the grey plug. This has to be done anyway to repair the plug so let's just get it over with.
3) Loosen or remove the screws in the cable clamp for the strain relief assembly on both the silver and grey plugs.
4) Once you have the cable clamps loose or off, unscrew the remainder of the strain relief assembly from the main body of the plug. Do this for both the silver and the grey plug.
5) You should now be able to push some more of the grey cable into/through the main body of the silver plug. You should now be able to get a good look at the wires in the grey cable.
6) In its' simplest form a stepper motor consists of 2 separate sets of coils, hence the 4 conductors which are sometimes called A+, A-, B+ and B-. Using your multi-meter you should be able find which wires are A coil wires, and which wires are the B coil wires.
7) The pin assembly in the grey male plug is held into the main body by one or more screws. Remove the screw/s and you will be able to push the black cable into the grey plug. This will in turn push the pin assembly out of the main body. There might be some resistance to this as the pin assembly is keyed into the main body to keep it from twisting.

Once you have the pin assembly out of the main body of the of the grey plug that will tell us a couple of things:
A - If the color code for the black cable is the same as the grey cable color code. If they are the same, it's probably safe to assume that we can hook things back up pin to pin and we'll be good to go, By pin to pin, I mean that whatever color is any pin particular number on the male side, BETTER be connected to the same pin number on the female side.
B - If they aren't the same, well then we'll have more information than we do now. We figure out the next step, and we move on to it.

Don

 

[awake]

Steppers come in two flavors, unipolar or bipolar. (Here is the first link that came up under Google: The difference between unipolar and bipolar stepper motors.) There are also more modern hybrid varieties, but I'm guessing that does not apply to your equipment.

With four leads, chances are very high that you are dealing with a bipolar motor. If so, then you can do some simple testing with a multimeter. Check for continuity between the leads - you should have two pairs of leads, where each pair has continuity with its par but no continuity with the other pair. Now you have identified the two coils in the motor.

The next (and possibly harder) step is to identify what is coming out of the drive. If it were me, I would probably start by taking off panels to see if I can see what sort of driver is being used, and what the wiring is. Ideally, you will find that there is a recognizable stepper motor driver with A and B leads clearly marked - and either you can trace those to the end of the cable by color or by continuity testing.

If you can get this far, then you can hook up the A leads to one of the coils and the B leads to the other coil. Test and see - if it moves correctly, you're done. If it moves backwards from what is expected, you need to swap the leads to one coil.

If it starts emitting smoke, then I have no idea who gave you any of this advice. (Keep in mind what you paid for this ... !)

 

[Unique2022]

Thanks for the info, the connectors are Amphenol pre 1997, If this helps.

 

[bdrmachine]

If you need replacement connectors and can't read any part numbers off them contact the company 1 (203) 265-8900, I believe. I had a connector I couldn't ID a few months back. After sending them photos they returned part numbers and retail source info.

 

[awake]

Thanks for the info, the connectors are Amphenol pre 1997, If this helps.

No, there is no particular standard with regard to a type of connector or the order of the pins. That was simply the choice of the machine manufacturer.

 

[RM-MN]

Unless you have shielded cable bonded to the Amphenol connector any type connector will suffice. On the flip side of this, if you have problems with the CNC or DRO especially, shielded cables are a big help.

 

[ddmckee54]

If this was a factory installation, a shielded cable would/should have had the shields connected together through a separate pin in the plugs. Since there are only 4 pins in the plugs I'd bet my money on unshielded cables. Once he gets the plugs opened up a little more we'll have more information.

Unique2022 - Out of idle curiosity, why did you say the connectors were pre-1997?

 

[Unique2022]

Thanks very much all resolved with some intricate work with individual connectors.

 

[ddmckee54]

As long as that's just a temporary fix to see if everything still works - it'll do the job. Right now you've got nothing to protect the connections from any schmutz that the mill throws out. (Or from any objects that might get dropped on them.)

For a more permanent solution you might want to consider a short section of terminal strip in a small experimenter's box. (A small electrical box would do also, that way you could continue to use the Wago connectors. You just want something with some strain reliefs and a cover.) That way you would have strain reliefs to support the cables, the box would protect the connections from dropped objects, and the cover would keep the schmutz out of the connections.

 

[ddmckee54]

Wait a minute, I'm only seeing 3 Wago connectors, or is the 4th Wago hidden behind the other 3?

Does this machine have limit switches? If so, that cable probably goes to the limit switch for the axis, and not the stepper motor like we originally thought. That would explain why the connection to pin 1 on the plug looked so bad, it wansn't actually used. A single pole limit switch requires a maximun of 3 wires, one to the Common contact, one to the Normally Open contact, and the other to the Normally Closed contact.