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
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 20. 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.
