7. MODBUS
IMS01J02-E4
123
Continued from the previous page.
Name
Attri-
bute
Struc-
ture
Data range
Factory
set value
PID/AT transfer *
[H-TIO-
, H-CIO-A,
H-SIO-A]
R/W
C
0: PID control operation
1: AT (Autotuning) operation
0
* Autotuning (AT) is the function which automatically measures, calculates and sets the optimum PID
constants according to the set temperature.
Caution for using the Autotuning (AT)
When a temperature change (UP and/or Down) is 1C or less per minute during
Autotuning, Autotuning may be cancelled before calculating PID values. In that case,
adjust the PID values manually. Manual setting of PID values may also be necessary if
the set value is around the ambient temperature or is close to the maximum
temperature achieved by the load.
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:
Operation mode conditions:
Auto/Manual transfer
Auto mode
PID/AT transfer
PID control mode
Control RUN/STOP transfer
Control RUN mode
The Measured value (PV) is without input error range [Input error determination point (high)
Measured value (PV)
Input error determination point (low)].
The output limiter high limit should be more than 0.1 % and the output limiter low limit should be
less than 99.9 %.
When Operation mode is set to “Normal (Can be controlled ).”
When the autotuning is finished, the display of each channel automatically returns to “0: PID control
operation.”
Conditions which will cause the autotuning to stop:
When the Temperature set value (SV) is changed.
When the Memory area is changed.
When the PV bias value is changed.
When the AT bias value is changed.
When transfer to Manual mode using the Auto/Manual transfer.
When the Measured value (PV) goes to input error range [Measured value (PV)
Input error
determination point (high) or Input error determination point (low)
Measured value (PV)].
When the power is cut off.
When FAIL occurs in the module whose channel is under the autotuning. Otherwise, when FAIL
occurs in the H-PCP-J module.
When transfer to the PID control mode by the PID/AT transfer.
When Operation mode is set to Unused, Monitor or Alarm.
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 control mode. The PID constants
return to the values at the start of the autotuning.
Continued on the next page.
