InView P22R DH485 Comms Loses Program

[thoffman]

I have an InView P22R with the external 2706-PDH485P comm module. The module requires external +24VDC to operate. It is configured (programmed) when downloading the message file to the P22R. The system works fine until the power is cycled. The PDH485P almost always loses its configuration when power is lost. The InView must be reprogrammed to resume operation. Needless to say, this is more than an inconvenience. In order to keep the system running, I added a continuous 24VDC supply for the comm module that doesn't turn off when the PLC is powered off. Occasionally mains power is lost and it's back to reprogramming. AB tech support insists this is impossible, but it happens. I found a Distributor in Austrailia that has the same problem. Any ideas on how to fix this?

 

[Ken Roach]

The guts of one of those communication modules is the motherboard of a PanelView 550 terminal, which have been the same board for a very long time. If the board is malfunctioning, I would suspect it is defective, rather than there being a configuration, wiring, or design problem.

My recollection is that these units use onboard flash memory rather than battery backup. Visually check to be sure.

 

[thoffman]

Thanks Ken. You're right, there's no battery - it's the first thing I looked for. I had no idea it was a PV550 board. I figured it was a patch board made by a 3rd party, as the AB guys didn't know much about it.