PAT (Position Analog Transmitter)

Shaft Encoder

Part # 93821


The Position Analog Transmitter (PAT) is a stand-alone water level shaft encoder. The PAT is ideal for industrial and hydropower application with a 4-20 mA output. A precision potentiometer is the measuring element, and a number of ranges are available, depending on gear selection.

The PAT can also provide 0.2 to 1 or 1 to 5 VDC output, depending on the external barrier strip connections. When operated with Stevens instruments, the PAT obtains its power from the receiving device. If operated as a stand-alone transmitter, the user must provide power, typically from 13 to 40 VDC.

The PAT is housed in an aluminum enclosure. The cover may be removed for access to zero and span adjustments as well as the gears for major range changes. The basic PAT consists of a float pulley shaft coupled through a pair of gears to a precision potentiometer. English or metric ranges are selected by mounting either an 18 inch or 375 mm circumference float pulley.

The output of the potentiometer drives a circuit which converts the input shaft position to a 4 to 20 mA signal. Zero and span potentiometers provide a means to set the PAT range within limits for each model. Two precision resistors permit selecting one of two voltage output ranges with jumpers on the external barrier strip.

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Technical Specifications


Shaft and pulley clamp to accept standard Stevens 18 inch or 375 mm circumference float pulley


4-20 mA, 0.2 to 1 or 1 to 5 VDC as selected on terminal strip.


Determined by selection of gears and potentiometer (see table below)


Ranges 0-2.5ft, 0-8ft, 0-10ft: 0.3 oz-in or less
All other ranges: 0.6 oz-in or less.


Thermal error less than 0.05% / °C. Other errors (not including float lag and line shift errors) are less than 0.75% for ranges 0-8ft and 0-10ft, and less than 0.38% for all other ranges. Accuracy calculations are based on the maximum head for any range in the adjustment band.

Operating temperature

-40 °C to +70 °C (-40 °F to +158 °F)

Power requirements

  • Supplied by connected Stevens instrument.
  • Receiver type 4-20 mA: 12.4 to 40 VDC must be supplied by the receiver or a power supply in series with the receiver.
  • Receiver type 0.2 to 1 VDC: 13.4 to 40.2 VDC must be supplied by a power supply.
  • Receiver type 1 to 5 VDC: 17.4 to 41 VDC must be supplied by a power supply.
  • The voltage supplied to the transmitter must be within these ranges, after taking loop circuit resistance into account.

Operating humidity

To 95% relative, non-condensing. This can be improved by installing fresh desiccant in the enclosure.


5.0” W x 6.4” L x 5.85” H, exclusive of mounting flanges and input shaft.


1.8 lbs (0.816 kg)


0.8 feet (0.2 m)

0-0.2 to 0-0.8 ft (0.05 to 0.2 m)

2.5 feet (0.6 m)

0-0.8 to 0-2.5 ft (0.2 to 0.6 m)

10 feet (2.6 m)

0-2.5 to 0-10 ft (0.65 to 2.6 m)

18 feet (4.6 m)

0-10 to 0-18 ft (2.6 to 4.6 m)

32 feet (8.1 m)

0-18 to 0-32 ft (4.6 to 8.1 m)

58 feet (14.5 m)

0-32 to 0-58 ft (8.1 to 14.5 m)

105 feet (26 m)

0-58 to 0-105 ft (14.5 to 26 m)