PLC-5 Question for Online Addition of Flex IO AI card on Remote IO Link


Thread Starter


Dear all,

I am facing an issue at site on a Process PLC (PLC-5) while trying to add 4 new AI channels for Flow Meters.

We have redundant racks containing PLC-5 (1785-L80C 1.5) Processors with BCM module and power supply in each.

The IO configuration is attached, All IO are connected via Remote IO originating CPU & going to BCM and then to Remote IO Adapters in each Rack.

We have Chassis 15 or Rack number 17 (a Flex IO node 1794-ASB on Remote IO) having only one 1794-IE8 Analog Input Card

My question is that "Can we add 2 more 1794-IE8 Analog Input Cards While Online". After Searching on Rockwell site and Knowledge base I am unable to find a document that states this activity is possible or provides a procedure. I am Assuming that it should be possible to Add a new Flex IO module 1794-IE8 in IO Configuration, and manually add BTW and BTR instructions and rungs using existing BT Files and existing N files and make these card work.

Thanks in Advance

bob peterson

I think the problem is going to be how do you change the dip switches
on the asb module and cycle power to the asb module to get it to
recognize the change without losing the signal for a few seconds.

If you can live with a few seconds of loss of these signals it's not
too difficult.

One hint is if you have a "redundant" system like this if you have to
change something in the CPU you can change it in one while the other
CPU is still running the old configuration.