Mighty Module Model SR2401 Thermocouple Input
Isolated Field Rangeable Two Wire Transmitter

Description

The SR2401 is a low-cost, reliable, thermocouple input two-wire transmitter for field or panel mounting in various industrial housings and enclosures.  It provides a DC output current (4/20 mA) proportional to a thermocouple input.

The SR2401 includes filtering and conditioning to reduce susceptibility to transients and noisy operations.  The SR2401 provides isolation by using a feedback VCO to develop a pulse train with a duty cycle proportional to the input signal amplitude.  This pulse train is coupled through a pulse transformer to the output circuitry, where the duty cycle data is converted to a 4/20 mADC output level proportional to the millivolt signal from the thermocouple.

Ranging is accomplished via a plug-in range card which characterizes the input to the desired thermocouple type and sets the temperature range and burnout protection (upscale or downscale).  Cold junction compensation is provided by a solid state temperature sensor embedded in the thermocouple input terminal strip.  The output ZERO and SPAN controls are accessible through the top of the case.  Zero is adjustable ± 20% and span ± 15%.  Terminations are made to screw terminal connectors on the top of the case.

Test points located on the transmitter's front panel allow verification of loop current value, using a milliammeter, without breaking the loop current.

Typical Application

Remote temperature data acquisition.  Elimination of ground loops and common mode signals.

Mounting

The SR2401 can be mounted in a thermocouple connection head (TSH-A6L), explosion-proof housing (XJAY), or on a flat surface using the two 4.5 mm diameter mounting holes provided. Standard 33 mm hole center spacing allows for mounting in most connection heads. The 5.08 mm center hole allows clearance for input wiring or for a 3/16 inch diameter temperature probe. An optional DIN-Rail mounting kit is available (DMP2000).

Specifications

INPUT RANGE Select any type thermocouple   (minimum span 4 mV) TEMPERATURE STABILITY ± 0.01% of span per°C POWER 10-36 VDC, polarity protected OUTPUT RANGE 4/20 mA Current limited = 35 mA SUPPLY VOLTAGE EFFECT 0.02% of span max 10-36 VDC ISOLATION Output to Input   1000 Volts RMS sine wave OPERATING TEMPERATURE -13°F to 176°F -25°C to  80°C

ACCURACY ± 0.1% of span INPUT IMPEDANCE 10 megohms LINEARITY Better than ± 0.05% of span (mV)   (input to output) COMMON MODE REJECTION 120 dB, DC to 60 Hz MAX LOAD RESISTANCE = [(V supply - 10)/20 mA] kilohms RESPONSE TIME - Step Change 250 ms for 99% of final value *  For linearized output see SC5000 series ** Within Specified Range Limits