Remote I/O comm error

I have a 1747-sn card talking to a 1749-asb with 1794-ir8 remote I/O. We lost the power supply that fed the 1749-asb and to make a long story short we lost the pwr supply that fed the 1794-asb and the remote I/O kept is last value, the error was not detected until some time had passed. I did some testing after the repair and I though Iread in the 1747-sn manual that I should be able to look at the processor status word 6 for fault detection, however when I mimic the power supply failure I see no change in status. Is there a easy way to detect a comm error on the remote I/O?

IIRC, there are some dipswitch settings that affect the rack fault status bits. Check the manual for the ASB and make sure you're looking at the correct revision of your ASB.

Paul

Yes you can. Look at page 4-28 in the 1747-SN manual. I'm using the 1747-SN w/ 4 scales. I wanted to detect a communication fault. So if it failed the scales would shut down and not over fill. I'm using logical rack 0 for the 4 scales which are 1/4 rack each.You copy data from the M1.Example
My SN card is in slot 12...
I used a copy file
source--#M1:12.10
dest----#B3:20
length--1
So B3:20/0..scale #1
B3:20/1..scale #2
B3:20/2..scale #3
B3:20/3..scale #4
These bits will always be a 1 as long as I have communications with the scales.
If I loose comm with scale #2..B3:20/1 goes to a 0. It workes for me hope this helps.
Terry

The 1794-ASB Rack Fault switch extends rack fault status to the module level. With a series E module, it is switch S2-6. With it on, module removal and insertion under power is possible, with it off, rack fault detection is extended to the module level.

This, plus Terry's very valuable advice should get you where you want to be.

Paul

Appreciate the replies.