I have a SLC500 CPU/03 with a 6" Panelview Component HMI. This is Allen-Bradley’s low cost Ethernet browser configured units with the software built into the device like a web page.

I had no issues developing the project, but I cannot seem to find a reference on which register reports communication health of the HMI. I suspect it should be within the(S) registers of the SLC 500. I need help in identifying the correct bit.

 

If you only have the serial connection to the PVc as comms to the SLC5/03, then the screen will bring up a warning of lost comms. However if you wish to check the DH485 comms to other devices then look at writing some plc code to create an alarm or status indicator from the status S2 file.

Grab/download a SLC500 user manual and have a read of what S addresses you want to look at.

 

Trevor,
I thought that S:1/7 was correct; however it represents the communication status of the programming port, not the RS-232. I looked a the S register in binary, removed the serial com cable, but never see any registers change. If I unplug my programming port, S:1/7 will go false. (I wrote an output to reflect the status)

WM

 

If anyone has the answer please respond. I have thought of a couple of things to try, one would be to use a latching switch on the PanelViewComponent and to monitor the BIT. I think this possible could be a problem after a power loss. If there is a way to look at the internal clock of the PVC from the PLC then I could use one of these BITS. Any suggestions?