Quote Originally Posted by itsmorefun View Post
it is indeed logical not to send a negative voltage in 0-10 volts I think it is implemented in the same way as for the temperature, when it is negative the relay is activated. see if the relay output activates when it is negative.

Gaël
That was a piece of the puzzle I was unaware of. It does send 0.5v to relay1 when it's above nominal value and 0v when below. Am I correct to assume that 0.5v is the relay output when on?