Omega Engineering CN9400 用户手册

Before embarking on the Advanced Settings, please

familiarise yourself with the basic operation of the controller

as described in this manual. The following instructions

assume that the user understands how to make the initial

configuration, can navigate through the Function Menu and

successfully Autotune the controller in heating mode.

Heat-Cool strategy is a feature that improves control of processes

that need heating and cooling, depending on the conditions, for

example:

Environmental test chambers used in rooms where the 

ambient temperature swings above and below the test 

temperature.

Plastics extruders where the material initially needs 

heating, then cooling, when it begins to heat itself 

exothermically due to pressure and friction applied by the

process.

The purpose of cool strategy is to maintain smooth control

of the process during transition from heating to cooling.

This is achieved by using PID control for heating and cooling with the

proportioning bands linked by an adjustable deadband.

From cold (normal procedure on a new installation)

Enter setpoint and allow the process to reach the setpoint using

factory settings for heating only.

Make the following pre-settings:

Level 1   set                  to

to 

and                  to 

Level 2  set                  to 

Level 1 set                  to 

Autotune will cause a temporary disturbance. Check that the

temperature has stabilised in heating mode before running the

process in cooling mode.

If regular temperature oscillations occur, change 

to optimum

value. See page 9. To select Autotune Calculated Cycle-time 

Autotune uses the same calculated 

value for both 

(heating) and 

(cooling). In some processes, regular temperature

oscillations occur when cooling.

Make the following manual adjustment:

In level 1 double the value of 

SP2.A

DAC

SP2.A

TUNE

CYC.T

CYC.2

BND.2