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Comment: The following text has been provided for project engineers. The text can be copied from this page and pasted into your word processor for inclusion in system specifications.

T420 Engineering Specifications

A 4-20 mA transmitter shall be provided to convert the sensed process variable from a nominal 0-5 VDC to 4-20 mA. The transmitter shall be 2 wire, 12 to 40 VDC loop-powered with its output proportional to the sensor input. The transmitter shall be UL Listed.

The transmitter shall provide easily accessible calibration and ranging adjustments. Offset shall be adjustable from 10-100% and Span shall be adjustable from 10-100% of the 5 Volt range.

The transmitter shall contain integral level simulation for ranging adjustments and system test purposes. The transmitter shall provide adjustable signal damping time constants of 0.1, 2 and 5 seconds.

The transmitter shall provide three levels of transient protection on the 4-20 mA loop: a gas tube arrestor for suppression of high voltages, transorbs, and varistors for fast clamping of lower voltage transients. The transmitter's output shall be measurable without disconnecting the loop power. The transmitter shall be a CONTEGRA Model T420.