Positive Control Regulators:
The normally closed (NC, Positive Control) regulator is used to
modulate the intake valve closed to control compressor output. The
valve is installed so that it senses compressor output pressure.
The NC regulator stays closed up to a pre-set
pressure. Once the valve opens, a pressure signal is output to
control the compressor.
Negative Control Regulators The normally open
(NO, Negative Control) regulator is used to modulate the intake
valve (or others) open to control compressor output. The valve is
installed so that it senses compressor output pressure. The NO
regulator stays open to a pre-set pressure sending
the compressor output pressure to the control system. Once the
valve starts closing, the pressure signal that is sent out, is
proportionally decreased compared to the compressor output
pressure.