INVT Goodrive350 Series Operation Manual page 301

Goodrive350 IP55 High-ingress Protection Series VFD
the capacitor needs to be added on the terminal of the PLC.

If a large number of meters or sensors are disturbed, it is recommended that you
configure an external C2 filter on the VFD input power end. For details, see section D.7
EMC filter.
7.7.2 Interference on RS485 communication
The interference described in this section on RS485 communication mainly includes
communication delay, out of synchronization, occasional power-off, or complete power-off that
occurs after the VFD is started.
If the communication cannot be implemented properly, regardless of whether the VFD is
running, the exception is not necessarily caused by interference. You can find out the causes
as follows:
1. Check whether the RS485 communication bus is disconnected or in poor contact.
2. Check whether the A and B wires of the RS485 communication bus are connected
reversely.
3. Check whether the communication protocol of the VFD is consistent with that of the host
controller. Check whether the communication protocol (such as the baud rate, data bits,
and check bit) of the VFD is consistent with that of the upper computer.
If you are sure that communication exceptions are caused by interference, you can resolve the
problem through the following measures:
1. Simple inspection
2. Arrange the communication cables and motor cables in different cable trays.
3. In multi-VFD application scenarios, adopt the chrysanthemum connection mode to
connect the communication cables between VFDs, which can improve the
anti-interference capability.
4. In multi-VFD application scenarios, check and ensure that the driving capacity of the
master is sufficient.
In the connection of multiple VFDs, you need to configure one 120 Ω terminal resistor at
5.
both ends.
Solution
1. 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).
2. Do not connect the VFD and motor to the same ground terminal as the upper computer
(PLC, HMI, and touch screen). It is recommended that you connect the VFD and motor
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Troubleshooting