Heartbeat between iFix HMI and Allen-Bradley PLC

I was wondering if anyone knew a way to go about creating a heartbeat between a PLC and an iFix HMI screen so that you can see when the PLC is out of run mode.

I'm sure there's more than one way to go about doing it, any input is greatly appreciated.

I did something similar on a tablet HMI that loses comm's.

I just put a flickering (2 seconds on/2 seconds off) bit for the HMI to read and use that as a visibility bit on the HMI. If it ever stays off or on longer than 4 seconds the comm's have been lost.

I am not very experienced in iFix, but if it has timers built in you could watch a flickering bit that runs two timers and if either timer get done show a comm's fault.

I run a 15 sec timer in plc logic. I monitor the elapsed time register in HMI. Then when elapsed time reaches 10 sec, I write "0" to timer count. PLC has alarm if timer times out.