Ability to link relays ([de]activation of a relay will [de]activate another)

[kizniche]

Feature request: When one relay is activated, one or more other relays are activated. This permits the PID controller or a conditional statement could activate more than one relay.

Consider the following simple relay configuration to illustrate the utility:

Relay 1 (Fan), GPIO 10, Link Relay 2 (when Relay 1 turns on, Relay 2 does also)
Relay 2 (Heater), GPIO 15

Relay 3 (Fan), GPIO 10, Link Relay 4 (when Relay 3 turns on, Relay 4 does also)
Relay 4 (Cooler), GPIO 20

Notice that the same GPIO can be set for multiple relays, which can produce a number of conflicts.

What if the same GPIO is trying to be turned on for different durations?
How do the threaded functions to turn on the relays communicate with each other and select the longest duration?

[kizniche]

Added in v3.5.73, commit 9eecb09

[kizniche]

What if the same GPIO is trying to be turned on for different durations?

I'll leave it to the user to not create conflicting conditional statements (i.e. I'm not putting in checks for all the possible crazy combinations).

How do the threaded functions to turn on the relays communicate with each other and select the longest duration?

With this iteration, they don't. It's whichever gets to the function first.

Consider this scenario:
Send first command: relay 3 on for 20 seconds.
relay 3 turns on for 20 seconds
Send second command (5 seconds after the first command): relay 3 on for 60 seconds.
Second command returns error that relay 3 is already on and does not extend the time on to 60 seconds.

I'm reopening this issue because this should be a high priority to fix. The solution is to extend the on duration.

Before activating any conditional statements or PID controllers, it's advised to thoroughly explore all possible scenarios and plan a configuration that eliminates relay conflicts. Then, trial run your configuration before connecting devices to the relays. Some devices or relays may respond atypically or fail when switched many times in rapid succession. Therefore, avoid creating a condition for a relay to switch on and off in an infinite loop.

[kizniche]

Issue fixed in commit 6e4a793