OTEK's model 900 is discontinued. The Series 900 is the Industry’s First Loop Powered Controller, that requires no power supply to give you on-off & proportional control of your process. The Series 900 is the Industry’s First Loop Powered Controller, that requires no power supply to give you on-off & proportional control of your process. The 900 Series can be ordered as a 4-20mA Transmitter Only; Transmitter with Display; Transmitter with Controller; Display only; Controller Only, Controller with Display or as Transmitter with Display & Controller. They are all Loop Powered in one small package, which is available in three grades: Explosion Proof; Sanitary (IP65) or Industrial.Mounting:You can mount the 900 Commercial Case virtually anywhere such as chassis, panel (front or behind), pipe (use “U” bracket), Din Rail (specify DIN Rail mounting) or just stick it to the wall. The Sanitary Nema 4X (IP65) option can be mounted on a wall, panel or pipe (use 2ea 2¼” U bracket). Power Supply Considerations: You can add as many “Loads” in series with the current loop, limited by the min-max compliance voltage. IE: Transmitter Only: 8-36V, Transmitter-Controller: 14-42V, TransmitterCont. & Display: 16-44V. See Speci?cations. Controller: Two opto-isolated open collector transistors controlled by dual comparators with hysteresis and delay (0.5 sec. to avoid noise) will control on-off your process. Limits’ adjustment is via the 12 turn potentiometers labeled LL & HL, the LEDs give you visual indication (yellow & red) of set point status. Transmitter: The 900 Series has two adjustments for the current loop output, zero & span with 12 turn potentiometers labeled 4 & 20 (mA). The analog signal conditioner’s output is used to drive the high accuracy monolithic current loop (4-20mA Transmitter). Display: The optional built-in display has 3½ digits (1999 max) with 0.5” LCD digits and it’s loop driven as well. There are two adjustments for the display, zero & span (Z & S). Decimal points must be speci? ed at time of ordering. Protection: The 900 Series is double zener protected (at the current loop inputs) for reversed input & up to 40VDC & 100mADC. Isolation: Input signals must be electrically isolated from the loop’s power by at least, 1 Mega Ohm.