RKC INSTRUMENT Z-TIO-G, Instruction Manual, Page: 121 / 246

9. COMMUNICATION DATA DESCRIPTION
IMS01T28-E4
9-13
PID/AT transfer
RKC communication
identifier G1
Modbus
register address ch1: 0061H (97)
ch2: 0062H (98)
Activation or deactivation of the Autotuning (AT) function is selected.
Attribute:
R/W
Digits:
1 digit
Number of data:
2 (Data of each channel)
Data range:
0: PID control
1: Autotuning (AT)
Factory set value:
0
Related parameters:
AT bias (P. 9-74), AT cycles (P. 9-75), Output value with AT turned on (P. 9-76),
Output value with AT turned off (P. 9-76), AT differential gap time (P. 9-77),
Proportional band adjusting factor (P. 9-78), Integral time adjusting factor (P. 9-78),
Derivative time adjusting factor (P. 9-78),
Proportional band limiter (high/low) (P. 9-79),
Integral time limiter (high/low) (P. 9-79),
Derivative time limiter (high/low) (P. 9-80),
Autotuning (AT):
The Autotuning (AT) function automatically measures, computes and sets the optimum PID values. The
Autotuning (AT) can be used for PID control (Direct action/Reverse action).
When the Autotuning (AT) is finished, the control will automatically returns to 0: PID control.
 Caution for using the Autotuning (AT)

When a temperature change (UP and/or Down) is 1

C or less per minute during Autotuning (AT),
Autotuning (AT) may not be finished normally. 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.

If the output change rate limiter is set, the optimum PID values may not be computed by Autotuning (AT).

When the cascade control is activated, the AT function cannot be turned on.
 Requirements for Autotuning (AT) start
Start the Autotuning (AT) when all following conditions are satisfied:
The Autotuning (AT) function can start from any state after power on, during a rise in temperature or in
stable control.
Operation
state
RUN/STOP transfer
RUN
PID/AT transfer
PID control
Auto/Manual transfer
Auto mode
Remote/Local transfer
Local mode
Parameter setting
Output limiter high

0.1 %, Output limiter low

99.9 %
Input value state
The Measured value (PV) is not underscale or over-scale.
Input error determination point (high)

Measured value (PV)

Input error
determination point (low)
Operation mode [Identifier: EI] (P. 9-37)
Control
Continued on the next page.