Issue with repeated failures of 1762-IR4

[rejoe.koshy]

Hey guys,
I am encountering a recurring failure of 1762-IR4 module for the past few months.I have replaced 3 modules in last 6 months.This module fails causing the PLC (micrologix 1500) to generate a fault & terminate its scanning cycle.

I have checked the RTDs connected to it & found it to be fine.What could be possible reason for this?

Note: Power outages in my facility is a little too much

Pls help!

 

[Logix_Stef]

Hey guys,
I am encountering a recurring failure of 1762-IR4 module for the past few months.I have replaced 3 modules in last 6 months.This module fails causing the PLC (micrologix 1500) to generate a fault & terminate its scanning cycle.

I have checked the RTDs connected to it & found it to be fine.What could be possible reason for this?

Note: Power outages in my facility is a little too much

Pls help!

If you can eliminate (100%) a wiring fault, send the most recent one to your nearest local AB distributor as it should be under warranty.

I could imagine, however, you have a ground/earth fault. Next time it fails, go online and interrogate the processor status, it should give you a hint what fault the processor generates.


If you have lots of power outages, a surge can kill the module
(if you have a ground fault, check your earthing arrangements and the RTDs resistance to ground/earth.

Stef.

 

[James Mcquade]

Since you have frequent power failures, may I suggest the following.

1. put a line filter in front of your plc to help with any signal spikes.
2. in regards to the failures, the next time you have this problem, look at the fault in the plc program before changing out the module. It may very well be that the module did not power up before the cpu. we have that problem here at times. The solution is to add in the last line of code an unlatch bit for fault over ride at power up S:1/8.

I would also cycle power to the plc as a verification test to see if the module comes up correctly.

james

 

[rejoe.koshy]

Since you have frequent power failures, may I suggest the following.

1. put a line filter in front of your plc to help with any signal spikes.
2. in regards to the failures, the next time you have this problem, look at the fault in the plc program before changing out the module. It may very well be that the module did not power up before the cpu. we have that problem here at times. The solution is to add in the last line of code an unlatch bit for fault over ride at power up S:1/8.

I would also cycle power to the plc as a verification test to see if the module comes up correctly.

james

Thanks for the wonderful insights!...
1.I checked for wiring issue -couldnt find any.
2.Ruling out the power up issue, since I have noticed faults in running conditions.

What remains is to see the fault code .....

Can module go faulty due to high temperature or due to frequent recycling of power (assuming there are no surges or spikes)?

 

[Mickey]

FYI,

A ML1500 does not use 1762 series of I/O modules.

Ml1200 and ML1100 do.

I agree that a UPS will help with power outages.

Can you tell us what the fault is? Description error code?