When The Digital Output Values Cannot Be Read - Mitsubishi Electric Q68AD-G User Manual

8
TROUBLESHOOTING
8.2.4

When the digital output values cannot be read

Check item
Is 24VDC external power supply being supplied? (Q66AD-DG
only)
Is there any fault with the analog signal lines such as disconnec-
tion (for the Q66AD-DG, disconnection of the signal line with the 2-
wire transmitter) or wire break?
Is the CPU module in the STOP status?
Are the offset/gain settings correct?
Is the input range setting correct?
Is the A/D conversion enable/disable setting for the channel to be
used set to A/D conversion disabled?
Is a large value set to the A/D conversion starting time setting (for
the 2-wire transmitter) (Q66AD-DG only)?
Has the operating condition setting request (Y9) been executed?
Is the value set for the averaging processing specification correct?
In the case of current input are terminals (V+) and (|+) connected ?
(For the Q68AD-G only)
The module may be faulty if the digital output values cannot be read after proper
corrective actions have been taken according to the above check items. Please
consult your local Mitsubishi representative.
8.2.4 When the digital output values cannot be read
Corrective action
Check that the external power supply terminals (between terminals
No. A19 and A20 or B19 and B20) are supplied with a 24VDC
voltage.
Check for faulty condition of the signal lines by a visual check and
a continuity check.
Set the CPU module to the RUN status.
Verify that the offset/gain settings are correct
(Refer to Section 4.6 and 5.6.2).
If the user range is being used, switch to a different default input
range and check if A/D conversion is correctly performed. If so
redo the offset/gain settings.
Check the Un\G20, Un\G21 in the monitor of GX Developer.
If the input range setting is incorrect, redo the GX Developer
intelligent function module switch setting
(Refer to Section 4.5).
Check the ON/OFF status with Un\G0 in GX Developer monitor
and review the initial setting of the sequence program or utility
package.
(Refer to Section 3.4).
Check the Un\G78 to Un\G83 in the monitor of GX Developer.
From GX Developer, turn the operating condition setting request
(Y9) from ON to OFF to check that the digital output values are
stored into the Un\G11 to Un\G18.
If so, review the initial setting of the sequence program or utility
package (Refer to Section 3.3).
• For the time averaging, set a value of "4 (times) x 10 (ms) x No. of
channels" or greater.
• For the primary delay filter, set a value of "10 (ms) x No. of chan-
nels" or greater.
If the above requirements are not met, 0 is stored as a digital
output value.
In the case of current input, connect terminals (V+) and (|+)
referring to Section 4.4.2.
8.2 Troubleshooting
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