Instruction manual

7. FUNCTIONS

IMSRM15-E6

117

(7) Cascade control

Cascade control monitors the controlled object temperature in the master unit and then corrects the set

value in the slave unit depending on the deviation between the target value (set value) and actual

temperature. The slave unit controls the non-controlled object. As a result, this control matches the

controlled object temperature to the target value.

This cascaded control is suitable when there is a large time lag between the heat source (heater) and

section whose temperature is necessary to be stabilized.

Cascade gain/Cascade bias

The conversion rate when the manipulated output (%) in the master channel is converted to the

relevant cascade signal (

C) can by changed from 0.0 to 100.0 % by the cascade gain.

The cascade bias is a bias added to the input value on the slave side for sensor correction, etc.

(8) Enhanced autotuning

The enhanced autotuning function is used to automatically measure, calculate and set the optimum

PID constants centering around the temperature set value. This function can start from any state after

power on, during a rise in temperature or in stable control. In addition, the AT bias can be set.

AT bias

The AT bias is set when the autotuning function in which the measured value (PV) does not exceed

the set value (SV) is activated. Our autotuning method performs ON/OFF control centering around the

set value (SV), then calculates and sets each of the PID constants by hunting the measured value (PV).

However, overshooting caused by this hunting may not be preferable depending on the controlled

object. In such a case, the desired AT bias is set.

If it is set, another set value (SV) to activate the autotuning function [AT point] can be set.

When AT bias is set to the minus (-) side

Measured value (PV)

Set value (SV)

AT point

T bias

Time