Omron output relay problem

[Bering C Sparky]

OK, no voltage between com and the outputs, and no continuity either

My question about the Jxx was because I was wondering if I had made a mistake in address, but that is not the case so I deleted it

Again I am not being clear. As per your diagram above, the Com on the output module is wired to 24v. I am testing between 0v and the outputs A0 to A7 and B0 to B7

No you are being pretty clear, I am just not aware of your background so trying to rule out the simple / obvious mistakes that are sometimes made.

BCS

 

[Bering C Sparky]

Ok after looking at the manual a bit more I got one more idea then I give up, so bear with me on this one.

Try to activate output #1 and see if you get continuity between A0 and B0.
Then de-activate output #1 and see if you no longer have continuity.

This is probably a dead end, but worth a shot from a perspective of flying blind.

EDIT:
I actually see one more possibility but it and what I talk about above would simply be you have the model # of the card wrong.
Not saying you do, just saying it would explain a lot.
See if your model # is not a OD211 by chance or a OC201.
If this is not the case then you have a strange situation indeed.

Good Luck,
BCS

 

[Banker]

Can you har the relay in the cardigan when you activate a output?

 

[Ronnie Sullivan]

If it's in his cardigan it's not going to work at all

 

[James Mcquade]

alphatargets,

If your willing, let's do this.

1. remove all modules from the plc.
2. clear the program and write a simple program to test the base unit itself (if there is one) to verify the cpu is not bad.
3. add the module in question, and I am assuming its a relay module. Remove all wiring.
4. add code to test one of the outputs.
5. have the output turned off and test the contacts with an ohm meter (a8 (com) to a0-a7 or B8 (c0m) to b0-b7) they should be open.
6. energize the output and test the contact again. there should be zero ohms.
if the wiring from the base unit to the card is correct and everything is working, you should see an ohm change.

I am going to explain the wiring as if the plc module will be supplying the power to the device.

1. Connect the AC (L1 line) or DC+ to the Com terminals.
2. when the outputs are energized, the contacts will close or the transistor will turn on to provide power to the device.
3. wire one side of the device to the outputs A0-a7 or B0-b7.
AC power should not matter but pay attention to the DC wiring per the instructions.
4. connect the other side of the device to the ac neutral or dc common.

Since I do not know what level of knowledge you have, I put it in as simple instructions.

regards,
james

 

[alphatargets]

No continuity between any of the outputs, and no clicking in the cardigan (nor the module casing!)

 

[alphatargets]

Hi James,

I have already done all of that, and am testing with all wiring removed. At the moment I have just the CPU and the output module connected. I have cleared the memory, and loaded a program that only activates relays 1 to 4. Same symptoms. Either there is something in the setup (do these things have a bios?) or some fried hardware. I have tried a couple of different output modules and they are all the same. All hardware is new. I am new to PLC programming, but not new to electrics.

The conundrum is that the indicator LEDs are lit when they should be, which tells me the CPU is sending out the correct instruction, but the coil is still not energising.

 

[alphatargets]

A wild thought, do you think the -ve should be tied to the ground ?

 

[Bering C Sparky]

If your model # is what you say it is then these seem to be your only options.
Right from the trouble shooting manual.

 

[alphatargets]

Well that's that then. I will get a new CPU next week and let you all know how it goes. Thanks for all of your suggestions and help, and of course taking the time to get involved, have a great weekend !

 

[JRB]

If a removable wiring connector that plugs into the front of the output card exists;

Try disconnecting all wiring to the connector, and use an ohmmeter across the COM and respective relay output terminal(s),
(which it sounds like you have already done), but do it with, and then without the wiring connector by finding the corresponding pins
when the connector is removed. Maybe there's something wrong with that connector and the problem transfers to any card connected
to it.

Is the connector fully seated? Visually inspect all connectors for damage.

Check for bent or retracted pins or blocked holes in any connectors, including the side connector on the output card and processor,
and power supply, reseat everything. Is a conductive termination connector required for the last or only card side connector?

If you can't get continuity from COM to each output contact when turned on, there's no use connecting a load at this point.

 

[alphatargets]

Hi JRB, thanks for the suggestions, I have already tried different connectors and three different output modules (without wiring) and I now assume the CPU has the problem, so I will be getting another one.

 

[hinddhindsa]

Please replace the fault relay with the unused relay in PLC , take help from a electrician for doing the soldiering if required.
or else if you can online with PLC, change the address of this relay with the un-used relay in PLC and do the rewiring by removing connections from the faulty relay to the New relay.

 

[hinddhindsa]

As you found the plc has gone faulty , always remember to take the back up & save in your computer. Purchase a new PLC CPU, and download the program in CPU, and power up the machine.
i HOPE IT HELPS YOU.
Thank You.

 

[alphatargets]

Thanks dude, that was really useful......