Lightobject.com Support Forum

I need to Keep a small chamber at 40C with a SSR connected to 48v dc fans. (I am burning in equipement 12hrs)

The internal relays worked fine and hold 40c plus/minus 1 degree, but they cycle very freqently and I don't think they would last long.
I installed a 50A dc ssr and cannot get it to function properly.
The ssr output starts at -2.5v at room temp. When the temp hits SV (40c) the volage goes to +9v
The -2 volts is keeping the relay on which means the relay is always on.


2 Questions.
How do I make the ssr output work off/on at SV?
How do I eliminate the ssr output from putting out voltage when not at or close to SV?

SSR won't be off completely even when it getting closed to the 'SV'
It will send out a 'pulse' to the SSR with either higher rate or less. When the temperature is far from the SV, the output signal look like "DC" at about 8~9V. When temperature getting very closed or even at SV, it send puse voltage in a few seconds or could be once a minute.

SSR won't turn on wht negative signal. I'll say "impossible". The SSR is drving by a LED and a LED never turn On when appying it negative.


Marco

I would add that you should be sure that the SSR is connected with the correct polarity -- the + output of the controller goes to the + input of the SSR. Same with the - out and in. If these are reversed, you'll get strange results.