RS-485 communications error (Communications port 2)
Phenomena A communications error occurred during RS-485 communications.
Possible Causes Check and Measures
(1) Communications conditions of
the inverter do not match that of
the host equipment.
Compare the settings of the function codes (y01 to y10, y11 to y20) with
those of the host equipment.
Correct any settings that differ.
(2) Even though no-response error
detection time (y08, y18) has
been set, communications is not
performed within the specified
cycle.
Check the host equipment.
Change the settings of host equipment software or disable the
no-response error detection (y08, y18 = 0).
(3) The host equipment did not
operate due to defective
software, settings, or defective
hardware.
Check the host equipment (e.g., PLCs and personal computers).
Remove the cause of the equipment error.
(4) The RS-485 converter did not
operate due to incorrect
connections and settings, or
defective hardware.
Check the RS-485 converter (e.g., check for poor contact).
Change the various RS-485 converter settings, reconnect the wires,
or replace hardware with recommended devices as appropriate.
(5) Broken communications cable
or poor contact.
Check the continuity of the cables, contacts and connections.
Replace the cable.
(6) The inverter was affected by
strong electrical noise.
Check if appropriate noise control measures have been implemented
(e.g., correct grounding and routing of communications cables and main
circuit wires).
Implement noise control measures.
Implement noise reduction measures on the host side.
Replace the RS-485 converter with a recommended insulated one.
(7) Terminating resistor is not
properly configured.
Check that the inverter serves as a terminating device in the network.
Set terminal resistor changeover switches for RS-485
communications (SW2/SW6) correctly.
In other words, turn the switch(es) to ON if required.
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