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35 CPU MODULE BUILT-IN ANALOG FUNCTION
35.6 Function (PID Control Via Parameter)
• For execution in the event of an error
■Precautions
• Even when "To Use or Not to Use Auto-tuning" is set to "Auto tuning used" while the PID control function being executed,
auto tuning is not executed.
• When the ambient temperature setting is enabled, if the relation (which is higher) between the target value (SV) and the
ambient temperature setting at the start of PID control (at the start of auto tuning) is changed after completion of auto
tuning, the accuracy of PID control goes down.
• When the ambient temperature setting is enabled, even if the relation (which is higher) between the target value (SV) and
the ambient temperature setting is changed during auto tuning, the change is ignored. The change in the ambient
temperature setting becomes valid after completion of auto tuning (during PID control).
• When PID control is stopped by setting on and off to the PID control execution command, the devices for the following
parameters are cleared.
(1) If a PID control stop error occurs while auto tuning is being executed, the system sets the following and stops auto tuning. (Since auto tuning is not
completed, "PID Control Execution Status" is not set to on.)
• Set on to "PID Control Function Error Display".
• Set the corresponding error code to "PID Control Function Error Code".
• Set off to "Auto-tuning Execution Status".
(2) Since the system does not set off to "PID Control Execution Command", the user needs to write off when executing auto tuning again.
(3) When the user writes on to "PID Control Execution Command", the system sets the following and executes auto tuning again.
• Set off to "PID Control Function Error Display".
• Set 0 to "PID Control Function Error Code".
(4) If a PID control continuation error occurs while auto tuning is being executed, the system sets the following, but auto tuning continues without changing
"Auto-tuning Execution Status".
• Set on to "PID Control Function Error Display".
• Set the corresponding error code to "PID Control Function Error Code".
• When auto tuning is completed, the system sets off to "Auto-tuning Execution Status" and on to "PID Control Execution Status" to execute the PID control
function.
(5) Since the PID control function is executed normally, the user sets off to "PID Control Execution Command" to end the PID control function.
• Set off to the control output.
• Clear the output value (MV), output value for heating (MVh), and output value for cooling (MVc) to 0.
• Set off to the temperature rise judgment flag.
• Set off to the PID control execution status.
• Set off to the auto tuning execution status.
OFF
ON
OFF
ON
OFF
ON
OFF
OFF
ON
Power off → on,
Reset → Reset clear
PID control function being
executed (stop error)
PID control function being
executed (continuation error)
Time
PID control execution command
Auto tuning used/not used
Auto tuning execution status
PID control execution status
PID control function error indication
PID control function error code 0: Unset xxxx (Error code)xxxx (Error code)
0: Unset
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