Festo CPX-AB Series Electronic Manual page 213

A. Technical appendix
1
Sensor 4 ... 20 mA
2
Positive sensor
voltage
3
Negative sensor
voltage
4
Connections to
analogue CPX module
Fig. A/5: Registering bipolar voltage signals with 2 inputs
Festo P.BE−CPX−AX−EN en 0503b
Connecting the sensor for bipolar voltage signals
Note
With this connecton variant, the following measuring faults
occur when the analogue value is registered:
overlapping of the value range in the vicinity of 0 V
(offset fault of the input amplifier)
symmetry fault in respect of the zero point (0 V).
1
+
IUx+
IUx−
IU(x+1)+
IU(x+1)−
2
3
4
A−15