Determining the state of auxilliary inputs

What is the most reliable way to determine the state of an auxiliary input (via L5500AUX unit)?

I have some inputs set as "bell push" but the state of the inputs changes infrequently and although nothing else *should* be changing those group addresses, for whatever reason the state of the group address does not reliably match the state of the input. I'm not sure if noise on the input might be causing multiple transitions and some are getting "lost", but I have 8 inputs on 8 different units across 3 different networks all of which were showing the wrong state when I last checked them.

By "infrequently" I mean that this is an alarm input from another system and should not change (should be "ON") for months at a time. During that time it is likely that the network will lose C-Bus or power for periods.

Just to clarify: I have relay units which use logic to prevent some outputs coming on if the group set by the aux input is not set. Those outputs were not on even though the input was on. Toolkit reported the value of the group address as zero. (Given that Toolkit/C-gate were not running when the last state change occurred I'm not sure where they got the status from.) Each input is used within the logic of multiple relay units spread across the network, all those units' outputs were off, suggesting that either the group ON message was not sent at all, or a subsequent OFF message was sent (but no units other than the aux's should be writing to that group), or the bus was somehow "down" when the ON was sent. And whatever happened was repeatable across multiple devices on multiple networks.

 

Make sure that you have the "Broadcast on power up" ticked in the genral tab and "restore to previous levels" ticked in the power fail tab.

 

Cool, that should help. (I thought I had "broadcast on power up" already set but it appears not, but "restore to previous levels" I'd missed altogether.)

If I understand correctly, even with these set as described, the input still won't be "read" on power up, though, just the last known state will be restored? What happens if the input changes state while the unit is not powered?

Also, I'm still not sure I can see what would have reset the relay channels. Assuming they also lost power they should have recovered the last known state anyway (ie ON), and if the AUX never broadcast any changes what would have caused the relay outputs to go off?

The only think I can think of is that the AUX unit has never seen the input close (it having always been closed when it was powered up) and never sent the ON signal but that seems very unlikely knowing the building, especially to have been the case on multiple units across multiple networks.

 

I remember a job that I had the same problem years ago. (in the end I put the C-Bus power supply on the UPS circuit, which fixed the issue) I think if the input changed from Open(off) to closed(on) during the power down it picked it up but if it changed from closed(on) to open(off) it missed it at times. It's always hard with power down problems

Prehaps the restore on power fail in the aux input unit. it might be sent to restore to off. Which means the input could be ON but you forced the aux to turn it OFF and it won't come back on again until it does a ON/OFF cycle

 

Update: I have made the changes discussed on site and so far things do seem better.

Thanks for the help.