RHEONIK Messgeräte GmbH
REV. I, Apr. 2004
.
Operation Manual RHE 07, 08, 11
Page
31
Using a digital voltmeter the voltages can be checked:
Terminal Circuit
Voltage
1
Drive +
0.3 - 7 V AC (terminal 1 - 2)
2 Drive
-
3
PT100
130 mV DC at 20 °C (terminal 3 - 4)
4 PT100
5
PT100
130 mV DC at 20°C (terminal 3 - 5)
6
Coil 1 +
10 - 150 mV AC (terminal 6 - 7)
7
Coil 1 -
8
Coil 2 -
9
Coil 2 +
10 - 150 mV AC (terminal 8 - 9)
If the values are within the above limits, the meter will oscillate normally.
If the measured voltages are not within the ranges shown in the table, disconnect the transmitter and
check the resistances at the sensor RHM terminals:
Terminal Circuit
Resistance
1
Drive +
5 - 170 Ohm (terminal 1 - 2)
2 Drive
-
3
PT100
107 - 109 Ohm at 20 °C (terminal 3 - 4)
4 PT100
5
PT100
0 Ohm (short circuit) (terminal 4 - 5)
6
Coil 1 +
30 - 150 Ohm (terminal 6 - 7)
7
Coil 1 -
8
Coil 2 -
9
Coil 2 +
30 - 150 Ohm (terminal 8 - 9)
If one of these values is infinite, the sensor RHM is defective.
Check insulation resistance to earth ground (sensor RHM housing).
If a short circuit between any sensor terminal and sensor housing is measured, the sensor RHM is
defective.
If no problems are located at the sensor resistance, check Sensor-to-Transmitter wiring for correct
connections and for no shorts or opens, loose conductors or poorly connected wiring.
