INVT Goodrive350 Series Operation Manual page 300

Goodrive350 IP55 High-ingress Protection Series VFD
displayed by a human-machine interaction device. The values are incorrectly displayed as
follows after the VFD is started:
1. The upper or lower limit is wrongly displayed, for example, 999 or -999.
2. The display of values jumps (usually occurring on pressure transmitters).
3. The display of values is stable, but there is a large deviation, for example, the temperature
is dozens of degrees higher than the common temperature (usually occurring on
thermocouples).
4. A signal collected by a sensor is not displayed but functions as a drive system running
feedback signal. For example, the VFD is expected to decelerate when the upper
pressure limit of the compressor is reached, but in actual running, it starts to decelerate
before the upper pressure limit is reached.
5. After the VFD is started, the display of all kinds of meters (such as frequency meter and
current meter) that are connected to the analog output (AO) terminal of the VFD is
severely affected, displaying the values incorrectly.
6. Proximity switches are used in the system. After the VFD is started, the indicator of a
proximity switch flickers, and the output level flips.
Solution
1. Check and ensure that the feedback cable of the sensor is 20 cm or farther away from the
motor cable.
2. Check and ensure that the ground wire of the motor is connected to the PE terminal of the
VFD (if the ground wire of the motor has been connected to the ground block, you need to
use a multimeter to measure and ensure that the resistance between the ground block
and PE terminal is lower than 1.5 Ω).
Try to add a safety capacitor of 0.1μF to the signal end of the feedback signal terminal of
3.
the sensor.
Try to add a safety capacitor of 0.1μF to the power end of the sensor meter (pay attention
4.
to the voltage of the power supply and the voltage endurance of the capacitor).
5. For interference on meters connected to the VFD AO terminal, if AO uses current signals
of 0 to 20 mA, add a capacitor of 0.47 μF between the AO and GND terminals; and if AO
uses voltage signals of 0 to 10 V, add a capacitor of 0.1 μF between the AO and GND
terminals.
Note:

When a decoupling capacitor is required, add it to the terminal of the device connected
to the sensor. For example, if a thermocouple is to transmit signals of 0 to 20 mA to a
temperature meter, the capacitor needs to be added on the terminal of the temperature
meter.; if an electronic ruler is to transmit signals of 0 to 30 V to a PLC signal terminal,
-282-
Troubleshooting