5. COMMUNICATION IDENTIFIERS
IMSRM04-E8
52
Autotuning conditions
Autotuning (AT) is the function which automatically measures, calculates and sets the optimum PID
constants according to the set temperature. The following is the conditions necessary to carry out
autotuning and the conditions which will cause the autotuning to stop.
Conditions necessary for autotuning:
The autotuning should be executed after satisfying all of the following conditions :
(1) Operation mode conditions:
z
Auto/Manual transfer (Identifier: J1):
Auto mode
z
PID/AT transfer (Identifier: G1):
PID mode
z
Control Run/Stop (Identifier: SR):
Control Run mode
(2) The input value should not be an underscale or overscale displayed.
(3) The output limiter high limit should be more than 0.1% and the output limiter low limit should be
less than 99.9%. (Setting by Initialize set communication)
(4) When operation mode is set to "Normal."
When the autotuning is finished, the mode display of each channel automatically returns to "PID."
Conditions which will cause the autotuning to stop:
z
When the set value (SV) is changed.
z
When the memory area is changed.
z
When the PV bias value is changed.
z
When the AT bias value is changed.
z
When transfer to Manual mode using the Auto/Manual transfer.
z
When the input value becomes an underscale or overscale display.
z
When the power is cut off.
z
When "FAIL" occurs in the module whose channel is under the autotuning. Otherwise, when
"FAIL" occurs in the PCP module.
z
When transfer to the PID mode by the PID/AT transfer.
z
When operation mode is set to "Normal."
z
When the Control Run/Stop function is changed to the "Control stop" function.
When the above-mentioned conditions to stop the autotuning occurs, the autotuning is
immediately stopped and switch over to the PID (PID control) mode. The PID constants
return to the values at the start of the autotuning.