User`s manual

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MELSEC-Q
8 TROUBLESHOOTING
8.2.4 When an analog output value is not output
Check item Action to be taken
Is 24VDC external power supply being supplied?
Verify that 24VDC voltage is being supplied to the external
power supply terminals (terminal numbers 16, 17).
Is there any fault with the analog signal lines such as broken
or disconnected line?
Check for any abnormality on the signal lines by doing a
visual check and performing a continuity check.
Is the CPU module in the STOP status? Set the CPU module to the RUN status.
Are the offset/gain settings correct?
Verify that the offset/gain settings are correct (see sections
4.6 and 5.6.2).
If the user range setting is being used, switch to a different
default input range and check if D/A conversion is correctly
performed. If it is correctly performed, redo the offset/gain
settings.
Is the output setting range correct?
Verify buffer memory address 20 (Un\G20) in GX Developer
monitor. If the output range setting is incorrect, redo GX
Developer intelligent function module switch settings (see
Section 4.5).
Is the D/A conversion enable/disable setting for the channel
to be output set to Disable?
Check the D/A conversion enable/disable setting using
buffer memory 0 (Un\G0) in GX Developer monitor and set it
to Enable using the sequence program or utility package
(see Section 3.4).
Is the D/A output enable/disable setting for the channel to be
output set to Disable?
Verify ON/OFF for the output enable/disable flags (Y1, 2) in
GX Developer monitor.
If the output enable/disable flags are OFF, review the initial
setting for the sequence program or utility package (see
Section 3.3).
Is the digital value being written to the channel to be output?
Verify buffer memory addresses 1, 2 (Un\G1, Un\G2) in GX
Developer monitor (see Section 3.4).
Has the operating condition setting request (Y9) been
executed?
Set the operating condition setting request (Y9) from ON to
OFF from GX Developer and check to see if the analog
output is normal.
If normal analog output is obtained, review the initial setting
for the sequence program or utility package (see Section
3.3).
POINT
If the analog output value is not output after the proper corrective action is taken in
accordance with the above check item, the possible cause is a module failure.
Consult the nearest sales representative or branch.