HeatBeat 1771-AM2 - RSLogix PLC-5

Hello,
Recently I suggested we make HearBeat monitors for some equipment.

The HeartBeats I'm familiar with require jumpering an input on a plc input module to an output and writing some logic to test communication between the two.

Anyhow, I was told you don't need a jumper and can use status bits to set up an internal HeartBeat for these types of modules. When I asked how people just shrugged their shoulders.

That's a blast from the past !

The 1771-AM2 is a small 1771 type I/O chassis (just two slots) with a built-in power supply and RIO adapter. It's functionally equivalent to having a 1771-ASB adapter and just filling the first two slots.

To monitor the status of this RIO adapter, or any other RIO adapter, you would use the Rack Status bits in the PLC-5.

It ashames me to say it, but I haven't had to work on a PLC-5 with Remote I/O for over ten years and have forgotten much of the details. You generally select an unused Data Table number and configure that to hold the IO Status info for the RIO channel (or maybe for all RIO channels), and get four status bits per logical rack to indicate the status of the devices.

The IO Status isn't the same as the Diagnostic file; the Diagnostic file has things like retry counters in it.

Ok, thanks. Still don't have it figured out, but this gives me a better idea what I'm even trying to do.

I believe this is what Ken is talking about. See picture and PDF

Great, Thanks Mickey.

Our logix program was created before I inherited it. The number 10 was already entered in S16, and the 4 I/O indications are generated in N10.

My boss says instead of a HeartBeat, it's sufficient to just monitor whether the I/O is faulted on compatible cards.

Typically, I use heartbeat monitors between pieces of equipment that run autonomously, just to make sure they are still out there working.