terlija
Member
Here is the scenario that I am sorting through.
Outputs in a flex I/O rack are commanded on off by a Foxboro DCS system logic via Devicenet to a Flex I/O 1794-ADN Devicenenet module .So with all outputs in a normal running state, power bump or loss occurs. DCS system is backed by UPS so output commands remain 'on' for typical 'enable' signals to VFD's, valves etc.. Power is returned to the Devicenet rack, but the outputs on the Devicenet reack remain off. We tried the HLS [ hold last state ] feature on the Devicenet Flex I/O communication module , but it did not set the outputs on after power up and comms reestablished.
Is there a reason for this that anyone is aware? It actually seems inconsistent as well. Like once, it actually recovered as expected, next power off simulation, the outputs stayed off aven though DSC is commanding off.
Thanks- Raylan
Outputs in a flex I/O rack are commanded on off by a Foxboro DCS system logic via Devicenet to a Flex I/O 1794-ADN Devicenenet module .So with all outputs in a normal running state, power bump or loss occurs. DCS system is backed by UPS so output commands remain 'on' for typical 'enable' signals to VFD's, valves etc.. Power is returned to the Devicenet rack, but the outputs on the Devicenet reack remain off. We tried the HLS [ hold last state ] feature on the Devicenet Flex I/O communication module , but it did not set the outputs on after power up and comms reestablished.
Is there a reason for this that anyone is aware? It actually seems inconsistent as well. Like once, it actually recovered as expected, next power off simulation, the outputs stayed off aven though DSC is commanding off.
Thanks- Raylan