Mitsubishi FX3UC SERIES User Manual page 408

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
Error PLC operation at
code error occurrence
Operation error [M8067(D8067)]
6750
6751
6752
6753
Continues
operation
6754
6755
6756
6757
6758
6759
402
Contents of error
<Step response method>
Improper auto tuning result
<Step response method>
Auto tuning operation direction mismatch
<Step response method>
Improper auto tuning operation
<Limit cycle method>
Abnormal output set value for auto tuning
[ULV (upper limit) ≤ LLV (lower limit)]
<Limit cycle method>
Abnormal PV threshold (hysteresis) set value for
auto tuning (SH < 0)
PV
<Limit cycle method>
Abnormal auto tuning transfer status
(Data of device controlling transfer status is
abnormally overwritten.)
<Limit cycle method>
Abnormal result due to excessive auto tuning
measurement time (τon > τ, τon < 0, τ < 0)
<Limit cycle method>
Auto tuning result exceeds proportional gain. (K
outside range from 0 to 32767)
<Limit cycle method>
Auto tuning result exceeds integral time.
(T = outside range from 0 to 32767)
I
<Limit cycle method>
Auto tuning result exceeds derivative time.
(T = outside range from 0 to 32767)
D
12 Test Operation, Adjustment, Maintenance and Troubleshooting
12.6 Judgment by Error Codes and Representation of Error Codes
Error codes in shaded columns are added in FX
<Auto tuning is finished. → PID operation is
started.>
• When auto tuning was started, the difference
between the measured value and the target
value was 150 or less. (SV − PV ≤ 150)
• When auto tuning was started, the difference
between the measured value and the target
value was 1/3 or more.
• 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
the result for improvement.
<Auto tuning is finished (K
operation is started.>
The variation of the measured value (PV) is small
=
P
compared with the output value. Multiply the
measured value (PV) by "10" so that the variation of
the measured value will increase during auto tuning.
<Auto tuning is finished (K
operation is 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
the result for improvement.
3UC
Action
) for auto tuning, and then check
PV
= 32767). → PID
P
= 32767). → PID
P
) for auto tuning, and then check
PV
PLCs.