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FX3S Series Programmable Controllers
User's Manual - Hardware Edition
14 Test Operation, Adjustment, Maintenance and Troubleshooting
14.6 Judgment by Error Codes and Representation of Error Codes
Operation error [M8067 (D8067)]
6740
Continues
operation
Sampling time (TS) Scan time
<Auto tuning is continued.>
The operation is continued in the condition "sampling time
(TS) = cyclic time (scan time)".
6742
Variation of measured value exceeds limit.
(PV < -32768 or +32767 < PV)
<PID operation is continued.>
The operation is continued with each parameter set to the
maximum or minimum value.
6743
Deviation exceeds limit.
(EV < -32768 or +32767 < EV)
6744
Integral result exceeds limit.
(Outside range from -32768 to +32767)
6745 Derivative value exceeds limit due to derivative gain (KD).
6746
Derivative result exceeds limit.
(Outside range from -32768 to +32767)
6747
PID operation result exceeds limit.
(Outside range from -32768 to +32767)
6748
PID output upper limit set value < PID output lower limit set
value.
<Transpose of output upper limit value and output lower limit
value. PID operation is continued.>
Check whether the target setting contents are correct.
6749
Abnormal PID input variation alarm set value or output
variation alarm set value (Set value < 0)
<Alarm output is not given. PID operation is continued.>
Check whether the target setting contents are correct.
6750
<Step response method>
Improper auto tuning result
<Auto tuning is finished. PID operation is started.>
• The deviation at start of auto tuning is 150 or less.
• The deviation at end of auto tuning is 1/3 or more of the
deviation at start of auto tuning.
Check the measured value and target value, and then execute
auto tuning again.
6751
<Step response method>
Auto tuning operation direction mismatch
<Auto tuning is forcibly finished. PID operation is not
started.>
The operation direction estimated from the measured value at
the start of auto tuning was different from the actual operation
direction of the output during auto tuning.
Correct the relationship among the target value, output value
for auto tuning, and the measured value, and then execute
auto tuning again.
6752
<Step response method>
Improper auto tuning result
<Auto tuning is finished. PID operation is not started.>
Because the set value was fluctuated during auto tuning, auto
tuning was not executed correctly.
Set the sampling time to a value larger than the output change
cycle, or set a larger value for the input filter constant.
After changing the setting, execute auto tuning again.
6753
<Limit cycle method>
Auto tuning operation direction mismatch
<Auto tuning is forcibly finished. PID operation is not
started.>
Check whether the target setting contents are correct.
6754
<Limit cycle method>
Abnormal PV threshold (hysteresis) set value for auto tuning
(SHPV < 0)
6755
<Limit cycle method>
Abnormal auto tuning transfer status
(Data of device controlling transfer status is abnormally
overwritten.)
<Auto tuning is forcibly finished. PID operation is not
started.>
Ensure that devices occupied by PID instruction are not
overwritten in the program.
6756
<Limit cycle method>
Abnormal result due to excessive auto tuning measurement
time (on > , on < 0, < 0)
<Auto tuning is forcibly finished. PID operation is not
started.>
The auto tuning time is longer than necessary.
Increase the difference (ULV - LLV) between the upper limit
and lower limit of the output value for auto tuning, set a
smaller value to the input filter constant (), or set a smaller
value to the PV threshold (SHPV) for auto tuning, and then
check the result for improvement.
Error
code
PLC
operation
at error
occurrence
Contents of error Action