The 1651C is a self-tuning, displayless pressure controller which operates from user-supplied ±15 VDC input power. Its compact size allows for installation anywhere on the process system, saving valuable rack space. The 1651 can be commanded through RS-232 communications, or it will accept an analog set point for pressure or position control. Alternately, there are five pre-programmable pressure or position set points which can be selected via TTL signals.