1769-L31 Run Mode

[MifPT]

Hello Everyone:

Every time that I power up the PLC, Rockwell 1769-L31, it goes strait to Fault and STOP, although the switch is in RUN position.
If I connect the PC to it, I can see the origin of the error: Power Supply Failure !!!

How can I put the PLC automatic in RUN mode without any faults as soon as I power him up?

thanks,
Miguel Ferreira

 

[jde777]

Hello Miguel

Is this an existing processor that just started faulting on power up or a new processor?

 

[MifPT]

Hello jde777:

This is a new PLC with new code, that I can't get it running as soon as I power up.

 

[jde777]

Is there any code in the fault handler routine?
Also list your rack layout. how many modules...ect..

 

[MifPT]

Ok,

The Fault Handler Routine just has one line
It's a SSV block with:
Class Name: Program
Instance Name: This
Attribute Name: MAJORFAULTRECORD
Source: MyFaulTag.TimeLow

MyFaultTag is a FaultRecord


The Hardware configuration is:
[1] to [5] are 32 Dig.Inputs - 1769-IQ32/A
[6] to [7] are 32 Dig.Outputs - 1769-OQ32/A
[8] 8 analogue inputs - 1769-IF8/A
[9] 8 analogue outputs - 1769-OF8V/A
[10] High Speed Counter - 1769-HSC


Thanks,
Miguel

 

[jde777]

Where does the power supply reside in this config? HSC has distance rating of 4 modules from the ps. Also could you try removing the rung from the fault handler and advise if same condition or not. what is the exact fault code you are getting as well. What power supply is being used? PA2,PA4....

 

[TWControls]

Also you do have the right end cap on the chassis don't you?

TW Controls -

http://www.twcontrols.com

 

[MifPT]

Yes, I have both end caps.

 

[TWControls]

Do you have a power up handler program?

TW Controls -

http://www.twcontrols.com

 

[Kiljoy]

I belive that we had the same problem on a MicroLogix 1500. We had too many cards for the base power supply, so we set our 4I analog card (via the on board switch) to external supply and hooked a sola 24VDC supply to it. The power supply fault kept popping up on boot. The problem ended up being the time it takes the processor to power up versus the analog card to power up and broadcast on the buss.
We had to remove the extra power supply and add the 1769-PA2 supply. Then set the analog card back to buss.
In summery, do not use external power supplies to power the analog cards and make sure the switches are all set to "Buss".