This is a 20-channel relay module that uses an analog signal as a detector for PLCs or a simple burglar alarm. Connect the module to a 24V power source. Use analog signals to activate relays.

Sanofi S.A. Part Cert 0.02% €8.03M ...

Before today, we probably would have said that scratch-built relay computers were the sole domain of only the most wizardly of graybeards. But this impressive build sent in by [Will Dana] shows ...