RKC INSTRUMENT Z-TIO-G, Instruction Manual

Page: 182 / 246

9. COMMUNICATION DATA DESCRIPTION
IMS01T28-E4
9-74
AT bias
RKC communication
identifier GB
Modbus
register address ch1: 0282H (642)
ch2: 0283H (643)
Use to set a bias to move the set value only when Autotuning is activated.
Attribute:
R/W
Digits:
7 digits
Number of data:
2 (Data of each channel)
Data range: 
Input span to

Input span
(Varies with the setting of the decimal point position.
However, even if "3: Three decimal places" is set, the maximum settable decimal places
are 2.)
Factory set value:
0.00
Related parameters:
PID/AT transfer (P. 9-13)
Function:
The AT bias is used to prevent overshoot during Autotuning in the application
which does not allow overshoot even during autotuning. RKC Autotuning method
uses ON/OFF control at the set value to compute the PID values.
However, if overshoot is a concern during Autotuning, the desired AT bias should
be set to lower the set point during Autotuning so that overshoot is prevented.
[Example] When AT bias is set to the minus (

) side.
Measured value (PV)
Set value (SV) 
AT point 
AT bias
Time
When the AT point exceeds the setting range, high (or low) limit of the setting range becomes the
AT point.