Dräger Polytron Ex, Инструкция по эксплуатации, Страница: 14 / 39

Installing Electrical Connections
Page 14 of 40
9023744 - 3rd edition - October 2005
Adjustment of Constant Current
(ex-factory-setting: 270 mA)
Note:
The procedure is valid for the transmitter Polytron Ex and Ex R, however the illustra-
tion only shows the transmitter Polytron Ex.
1 Check position of jumper and correct if required
(ex-factory setting).
2 Position jumper according to sensor current (see specifications in technical data
of the Ex-sensor used, page 25):
3 Attach cable of Ex-sensor.
4 Connect voltmeter (R
i
≥
10 MOhm, measurement error
≤
0,2 %) to test points.
● Switch on power supply.
5 Using potentiometer, adjust voltage at the test points
(for 270 mA: 891 mV, for 276 mA: 911 mV).
4 Disconnect voltmeter.
6 Screw upper section onto housing using the hexagon socket-head bolts.
— Repeated adjustment is not necessary if the Ex-sensor is subsequently replaced
by an Ex-sensor with the same adjustment current.
— Sensor replacement can be carried out without interrupting the supply voltage in
explosion-hazard areas, since the sensor circuit is intrinsically safe.
The ex-factory setting is Constant current, 270 mA (corresponding to 891 mV)
Sensor Current 100 to 140 mA:
Sensor Current 141 to 220 mA:
Sensor Current 221 to 300 mA:
(ex-factory setting)
brown
yellow
black
4 3
V
2
1
5
0
1
423
7
44_1_en.eps
0
1
523
7
44_1
.eps
6