Mitsubishi Electric MELSEQ FX3S Series User Manual page 144

FX Series Programmable Controllers
3S
User's Manual - Hardware Edition
PLC
Error operation
code at error
occurrence
Operation error [M8067 (D8067)]
6740 Sampling time (T
Variation of measured value exceeds limit.
6742
(PV < -32768 or +32767 < PV)
Deviation exceeds limit.
6743
(EV < -32768 or +32767 < EV)
Integral result exceeds limit.
6744
(Outside range from -32768 to +32767)
6745 Derivative value exceeds limit due to derivative gain (K
Derivative result exceeds limit.
6746
(Outside range from -32768 to +32767)
PID operation result exceeds limit.
6747
(Outside range from -32768 to +32767)
PID output upper limit set value < PID output lower limit set
6748
value.
Abnormal PID input variation alarm set value or output
6749
variation alarm set value (Set value < 0)
<Step response method>
6750
Improper auto tuning result
Continues
operation
<Step response method>
6751
Auto tuning operation direction mismatch
<Step response method>
6752
Improper auto tuning result
<Limit cycle method>
6753
Auto tuning operation direction mismatch
<Limit cycle method>
6754 Abnormal PV threshold (hysteresis) set value for auto tuning
(SH
PV
<Limit cycle method>
Abnormal auto tuning transfer status
6755
(Data of device controlling transfer status is abnormally
overwritten.)
<Limit cycle method>
6756 Abnormal result due to excessive auto tuning measurement
time (τon > τ, τon < 0, τ < 0)
138
Contents of error
) ≤ Scan time
S
< 0)
14 Test Operation, Adjustment, Maintenance and Troubleshooting
14.6 Judgment by Error Codes and Representation of Error Codes
<Auto tuning is continued.>
The operation is continued in the condition "sampling time
(T ) = cyclic time (scan time)".
S
<PID operation is continued.>
The operation is continued with each parameter set to the
maximum or minimum value.
).
D
<Transpose of output upper limit value and output lower limit
value. → PID operation is continued.>
Check whether the target setting contents are correct.
<Alarm output is not given. → PID operation is continued.>
Check whether the target setting contents are correct.
<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.
<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.
<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.
<Auto tuning is forcibly finished. → PID operation is not
started.>
Check whether the target setting contents are correct.
<Auto tuning is forcibly finished. → PID operation is not
started.>
Ensure that devices occupied by PID instruction are not
overwritten in the program.
<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 (α), or set a smaller
value to the PV threshold (SH
check the result for improvement.
Action
) for auto tuning, and then
PV