Instruction manual

4–3 Heat-Cool Control

n injection mold is required to be controlled at 120°C to ensure

a consistent quality for the parts. An oil pipe is buried in the mold.

Since plastics are injected at a higher temperature (e.g., 250°C),

the circulation oil needs to be cooled as its temperature rises.

Here is an example:

The PID heat-cool is used for the example at left. To

achieve this, set the following parameters in the setup

menu:

INPT=PT.DN

UNIT=°C

DP= 1-DP

OUT1=REVR

O1TY=RELY

CYC1=18.0 (sec.)

O1FT=0.0

OUT2=COOL

O2TY=4–20

O2FT=BPLS

Set SV at 120.0°C, CPB at 125(%) and DB at -4.0(%).

Apply auto-tuning at 120°C for a new system to get

optimal PID values. See section 3-11.

Adjustment of CPB is related to the cooling medium

used. If water is used as the cooling medium instead

of oil, the CPB should be set at 250(%). If air is used

as the cooling medium instead of oil, the CPB should

be set at 100(%).

The adjustment of DB is dependent on the system

requirements. A higher positive value of DB will pre-

vent unwanted cooling action, but will increase the

temperature overshoot, while a lower negative value

of DB will result in less temperature overshoot, but

will increase unwanted cooling action.