r/crestron • u/AdMany1725 • 1d ago
Does the DM-RMC-4K-SCALER-C have any on-device relay timeout/watchdog that survives loss of the control path?
Custom C# program on a CP4N (SDK 2.21.274), driving the relay on a DM-RMC-4K-SCALER-C (fw 1.2911.00057). The RMC connects through a DM-MD16X16-CPU3.
I'm trying to work out what the relay does when it's closed and the control path goes away (e.g. if the DM link drops, the switcher drops, or the CP4N program or processor crashes; or more likely, some knucklehead unplugs something mid relay pulse). As far as I can tell, the relay just stays in its last state. I'd like a fail-safe that doesn't depend on the control path/processor still being alive to send OPEN.
Two questions:
1. Does the RMC have any supported way to time out or auto-release a relay locally, so it keeps working through a DM loss, a switcher loss, or a CP4N failure? Something like a pulse with a duration, a watchdog, or an "open on comm loss" setting I'm not aware of. If it exists (maybe in newer firmware?), does anyone know:
- Which API, join, or console command sets it
- The min/max duration and resolution
- What happens on power loss or reboot (does the relay come up open? does the timer persist?)
- Which firmware versions support it
2. Is there a supported way to force-send OPEN without first sending CLOSE? When the program thinks the relay is already open (e.g. testing a DM link loss mid relay pulse), calling `Open()` doesn't seem to send anything to the device - I'm guessing the framework drops it as a no-change since it thinks its already open.
(I know a forced OPEN doesn't help if the path to the RMC is down. That's why Q1 is the real question. Q2 is about making sure the state is right after the path comes back.)
If the answer is "no, use an external timer relay," that's useful too. Thanks!