I've installed several banks of RCS rs485 controlled relays at a customer site for control of curtains. When these relays are energized to open the curtains, very often one of them won't latch(it's not the same relay every time). The led's indicate that they should be latched but they are stuck. If I tap on them I can get them to latch over. Other than the power supply being undersized, i.e. not delivering enough current, can anyone think of why this might happen or is this product just unreliable?
Thanks,
Joe

Ok, no responses that's alright. From my investigation, the RCS relay board design is unreliable (details below). Does anyone know of another serial controlled relay board I can use.

Debug details-
Of 8 relay boards being driven from 1 power supply, I disconnected 6, to verfiy that there was not a power supply problem. The voltages stays right at 12 V and the current drain is fairly small even with all 8 boards powered (I'm using a 1.2A supply). The relays are turned on in sequence, not all at once, again to make sure there isn't a large current drain which is preventing 1 from latching. Still no dice. The stuck relay, which is not always the same one, shows an led which means it should be on, a tap on the relay will cause it to latch properly. I tried disconnecting the load, even though I didn't know how that could be causing the problem, it wasn't. I even tried applying a larger voltage to the board to try to get the relay to pick up, but to no avail. Final conclusion - the RCS relay board is unreliable.

Check out http://www.eeci.com/ I've used these boards before with great results. Can order with 232 OR 485 control, and resonably priced.

i think you have too much load on the relay, so when it makes a connection makes a spark and lock in and does not release or some voltage still stays at the relay and won't let it release it.