The Model JH250 2-wire transmitter provides a 4/20mA current loop output proportional to the position of a potentiometer or slidewire wiper. A fixed-range device, it is precisely calibrated to your specified input range at the factory. Standard input calibration is 0/100% travel: it may be readjusted or factory-calibrated to any 50% or wider portion of the travel. Conformal coating protects the circuitry against condensation and corrosion in industrial atmospheres.
The JH250 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 JH250 does not provide input/output isolation.
Standard calibration is for 0/100% travel. If you wish, calibration can be factory-set for any 50% or wider input range. Simply specify on your order.
It is not necessary to specify the potentiometer’s resistance. Just make sure it is no less than 1Kohm nor more than 100Kohms.
Always dc loop powered.
Change model number to Model JH250-DIN. (See "Installation and Connections," below.)
INSTALLATION AND CONNECTIONS
The JH250 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 JH250-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: Potentiometer wiper.
Terminal B: Potentiometer cw (100% travel).
Terminal C: Potentiometer ccw (0% travel).
0 to 100% travel, or any 50% or wider portion of the travel (for example, 25 to 75% travel).
May be any resistance between 1Kohm and 100Kohms. It is not necessary to specify the potentiometer resistance on your order: end-to-end resistance does not affect the calibration.
4/20mA, 2-wire (loop-powered) output.
+/-0.1% of span.
Zero and span provide sufficient adjustability to allow recalibration to any 50% or wider portion of the input potentiometer’s travel.
+/-0.05% of span or better.
Under 100 milliseconds.
-40 to +80 deg. C (-40 to +176 deg. F).
+/-0.02% of span per deg. C, or better.
DC loop-powered. Requires at least 12Vdc at the transmitter’s output terminals. 36Vdc maximum.