6.3 If an Alarm Code Appears on the LED Monitor
6-14
[ 15 ] er8 RS-485 communication error (Communication port 1)/
erp RS-485 communication error (Communication port 2)
Phenomenon: A communication error occurred during RS-485 communication.
(1) Communication 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 (functoin codes
y08, y18) has been set,
communication 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 (function codes 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 communication 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 communication cables and main
circuit wires).
➔ Take noise countermeasures.
➔ Take noise reduction measures at 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 select switches for RS-485 communication
(SW3/SW2) correctly.
In other words, turn the switch(es) to ON if required.
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