Tuesday, 31 May 2011 02:05 Last Updated on Monday, 29 August 2011 01:09 Written by Administrator

MODEL JH240: 2-WIRE TRANSMITTER
RTD INPUT, FIXED RANGE, NONISOLATED

    • For 100 ohm Platinum RTDs - Linearized
    • Three-Wire Lead Resistance Compensation
    • Low-Drift Input Amplifier
    • Fits Standard Connection Heads
    • -40 to +80 Degree C Operation
    • DIN Rail mounting available

    JH240
    PDF
    DATA SHEET

The Model JH240 2-wire transmitter provides a 4/20mA current loop output proportional to temperature as measured by a 100 ohm platinum RTD (resistance thermometer). A fixed-range device, it is precisely calibrated to your specified input range at the factory. (For a rangeable 2-wire RTD transmitter see Model JH245.) RTD linearization is provided. Three-wire input circuitry eliminates errors due to lead wire resistance. Conformal coating protects the circuitry against condensation and corrosion in industrial atmospheres.

The JH240 is a loop-powered device. Connected in series between a 24Vdc supply and readout instruments, it receives its power from the 4/20mA output loop. A built-in LED indicates loop current: dim at 4mA, bright at 20mA. The JH240 does not provide input/output isolation.

ORDERING INFORMATION

Model Number: 

Model JH240.
Input Range:  

Specify any range allowed by the "Input Capabilities" spec, below.
RTD Type and Curve:  

100 ohm platinum RTD only. Standard DIN/IEC calibration is normally used. If a different platinum RTD curve is needed, please specify on your order.
Output Range: 

(Always 4/20mAdc.)
Power: 

(Always dc loop powered.)
DIN-Rail Mounting:  

Change model number to Model JH240-DIN. (See "Installation and Connections," below.)

INSTALLATION AND CONNECTIONS

The JH240 is 1-3/4 inches in diameter and is designed to fit many standard thermocouple-type connection heads. It may also be mounted to any surface using two #8 (or smaller) screws. An optional DIN-rail mounting clip (specify Model JH240-DIN) allows the transmitter to be snapped onto DIN rail. Width is 1-3/4 inches.

Connections are made to the transmitter’s terminal strip. Connections are:

"+" Terminal: Output/Power Loop. Receives current from (+) DC supply. 
"-" Terminal: Output/Power Loop. Passes on current to the next series loop device, or to the (-) supply. 
Terminal A: RTD (opposite end from Terminal C). 
Terminal B: RTD compensation (same end of RTD as Terminal C). 
Terminal C: RTD.

DETAILED SPECIFICATIONS

Input Capabilities:  

Minimum span 10 deg. C (18 deg. F). Maximum range includes the RTD’s full temperature range. Low end of range may be at zero degrees, elevated or suppressed.
RTD Type:  

100 ohm platinum RTD. Factory calibration is per DIN/IEC standard unless otherwise specified.
Output:  

4/20mA, 2-wire (loop-powered) output.
Accuracy (factory calibration): 

+/-0.1% of span or 0.05 deg C (0.09 deg F), whichever is greater.
Adjustability: 

Zero and span each are adjustable approx. +/-15% of span.
Response Time: 

Under 100 milliseconds.
Guaranteed Operating Temperature: 

-40 to +80 deg. C (-40 to +176 deg. F).
Temperature Stability: 

+/-(0.02% of span plus 0.005 deg C) per deg. C, or better.
Power Requirements: 

DC loop-powered. Requires at least 12Vdc at the transmitter’s output terminals. 36Vdc maximum.