44 Function Description
WAGO I/O System 750 XTR
750-495/040-010 3-Phase POM 20KV 300A XTR
Manual
Version 1.0.0
In the event of input overloading of the current or voltage measurement
inputs, the I/O module cannot digitize these values and limits the measured
values to the maximum measurable range (clipping of the current or voltage
measured values). As a result, the RMS value that is output is erroneous.
The more the input (and, thus, the reference points for RMS calculation) is
overdriven, the greater the measurement error is. This can also damage
the I/O module.
Voltage clipping due to input overloading is signaled by the “G” LED and
current clipping by the “C” LED.
All 3 error states are also indicated in the process image by setting the
corresponding bits in “Expanded status word 1,” byte 2.
The clipping limit is:
- 13.93 kV
RMS
for the voltage inputs
- 493.1 A
RMS
for the current inputs
2.
The I/O module is designed for operation at a constant line frequency
between 45 Hz and 65 Hz. With a constantly changing line frequency, the
measurement errors can be greater than indicated in section “Device
Description” > “Technical Data.”
3.
All 3 phases of the 3-phase network must be connected.
Observe limit values
Ensure that all limit values indicated in the technical data are observed. Values
above or below the limits can lead to destruction of the device.
Measurement Accuracy in Phase Angle Measurement
Measurement accuracy for phase angle measurement decreases with weaker
current and voltage signals.
Line affects measurement accuracy
The capacity of long measuring lines can cause a phase angle shift and thus
decrease to the measurement accuracy.