The MS123 module is functional equivalent of the USS123 and USS123P which converts the analog input signal (0 - 10V) from the controller to four discrete, voltageless output states. Relays have SPDT contacts.
Switching sequence: 0 S1 S1+S2 S1+S2+S3
The MS3 module is functional equivalent of the URAC3 and URAC3P which converts the analog input signal (0 - 10V) from the controller to four discrete, voltageless output states. Relays have SPDT contacts.