Fuji Electric FRENIC-HVAC User Manual page 649

[ 22 ] Er8 RS-485 communications error (COM port 1)
ErP RS-485 communications error (COM port 2)
Problem A communications error occurred during RS-485 communications.
Possible Causes
(1) Communications conditions of
the inverter do not match that of
the host equipment.
(2) Even though no-response error
detection time (y08, y18) has
been set, communications is not
performed within the specified
cycle.
(3) The host equipment did not
operate due to defective software,
settings, or defective hardware.
(4) The RS-485 converter did not
operate due to incorrect
connections and settings, or
defective hardware.
(5) Broken communications cable or
poor contact.
(6) Inverter affected by strong
electrical noise.
(7) Terminating resistor not properly
configured.
9.3 If an Alarm Code Appears on the Monitor
What to Check and Suggested Measures
Compare the settings of the y codes (y01 to y10, y11 to y20) with
those of the host equipment.
 Correct any settings that differ.
Check the host equipment.
 Change the settings of host equipment software or disable the
no-response error detection (y08, y18 = 0).
Check the host equipment (e.g., PLCs and personal computers).
 Remove the cause of the equipment error.
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.
Check the continuity of the cables, contacts and connections.
 Replace the cable.
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.
Check that the inverter serves as a terminating device in the network.
 Configure the terminating resistor switch(es) (SW2/SW3) for
RS-485 communication correctly. (That is, turn the switch(es) to
ON.)
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