Troubleshooting Of D/A Conversion - Mitsubishi Electric MELSEC L Series User Manual

11.6.2

Troubleshooting of D/A conversion

(1) When an analog output value is not output
Is the external power supply 24VDC supplied?
• Is the external power supply wired correctly?
• Is the external power supply 24VDC supplied within the specified
range?
Is there any problem with wiring, such as off or disconnection of analog
signal lines?
Is the CPU module in the STOP status?
Is the offset/gain setting correct?
Is the output range setting correct?
Is D/A conversion enable/disable setting (Un\G0) of the channel to
output data set to D/A conversion disable (1)?
Is CH Output enable/disable flag (Y1 to Y4) of the channel to output
data off?
Is any digital value written to the channel to output?
Is Operating condition setting request (Y9) being executed?
If the analog output value is not output even after the above actions are taken, the module may be failed. Please consult
your local Mitsubishi representative.
176
Check item
DA4
Action
Check External power supply READY flag (X7), and take the
following actions if the flag is off.
• Wire the external power supply referring to the wiring diagram.
( Page 50, Section 6.3)
• Supply the external power supply 24VDC within the performance
specifications. ( Page 24, Section 3.2)
Check the faulty area by checking the signal line visually or
conductively.
Change the status of the CPU module to RUN.
After turning OFF  ON  OFF Operating condition setting request
(Y9), compare the values of CH1 User range settings offset value
(Un\G210) to CH4 User range settings gain value (Un\G217) with
the values in the range reference tables. If the stored values are not
desired offset/gain values, perform the offset/gain setting again.
For the range reference table, refer to the following.
• Range reference tables (
Check Setting range (Un\G20). If the output range setting is
incorrect, correct the switch setting.
Check D/A conversion enable/disable setting (Un\G0), and set D/A
conversion enable (0) using a program or parameter setting.
Check the status of CH Output enable/disable flag (Y1 to Y4).
If CH Output enable/disable flag (Y1 to Y4) is off, review the
program. In addition, check that the CPU module is not in the STOP
status.
Check CH Digital value (Un\G1 to Un\G4).
Turn on and off Operating condition setting request (Y9) and check
that the analog output is performed properly.
If the analog output is performed properly, check the program on
whether the description of Operating condition setting request (Y9)
is correct.
Page 145, Section 8.12 (3))