854
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
37 Error Check Method and Error Code List
37.4 Error Code List and Action
Operation error [M8067(D8067)]
6750
Continues
operation
<Step response method>
Improper auto tuning result
<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.
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 operation
<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>
Abnormal output set value for auto tuning
[ULV (upper limit)
≤
LLV (lower limit)]
<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 (SH
PV
< 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 (
τ
on >
τ
,
τ
on < 0,
τ
< 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 (
α
), or set a smaller value to the PV
threshold (SH
PV
) for auto tuning, and then check
the result for improvement.
6757
<Limit cycle method>
Auto tuning result exceeds proportional gain. (K
P
=
outside range from 0 to 32767)
<Auto tuning is finished (K
P
= 32767).
→
PID
operation is started.>
The variation of the measured value (PV) is small
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.
6758
<Limit cycle method>
Auto tuning result exceeds integral time.
(T
I
= outside range from 0 to 32767)
<Auto tuning is finished (K
P
= 32767).
→
PID
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
PV
) for auto tuning, and then check
the result for improvement.
6759
<Limit cycle method>
Auto tuning result exceeds derivative time.
(T
D
= outside range from 0 to 32767)
Error codes in shaded columns are added in FX
3U
and FX
3UC
PLCs.
Error
code
PLC operation at
error occurrence
Contents of error
Action
