Connect-Tek Transa PRO 17 Bedienerhandbuch PDF herunterladen (Seite 32)

3–6 Heat-Cool Control

The heat-cool control can use one of six combinations of control modes. Setup of parameters for each control mode are shown in the

following table.

NOTE: The ON-OFF control may result in excessive overshoot

and undershoot problems in the process. The P (or PD) control

will result in a deviation process value from the set point. It is

recommended to use PID control for the heat-cool control to pro-

duce a stable and zero offset process value.

Other Setup Required: O1TY, CYC1, O2TY, CYC2,

A2SP, A2DV

O1TY and O2TY are set in accordance with the types of OUT1

and OUT2 installed. CYC1 and CYC2 are set according to the

output 1 type (O1TY) and output 2 type (O2TY). Generally,

select 0.5~2 seconds for CYC1 if SSRD or SSR is used for

O1TY. Select 10~20 seconds if relay is used for O1TY; CYC1 is

ignored if linear output is used. Similar conditions are applied to

CYC2 selection. If OUT2 is configured for ON-OFF control (by

selecting AL2), OUT2 will act as alarm output, and the process

alarm as well as deviation alarm (see sections 3-8 and 3-9) can

be used. Adjust A2SP to change the set point if process alarm is

used, and adjust SP1 (with preset A2DV) to change the set point

if deviation alarm is used.

Examples:

Heat PID+Cool ON-OFF: Set OUT1=REVR, A1FN or

A2FN=PV1.H, A1FN or A2MD=NORM, A1HY or A2HY=0.1,

PB1≠0, TI1≠0,TD1≠0, and set appropriate values for O1TY and

CYC1.

Heat PID+Cool PID: set OUT1=REVR, OUT2=COOL,

CPB=100, DB=-4.0, PB1≠0, TI1≠0, TD1≠0, and set appropriate

values for O1TY, CYC1, O2TY, CYC2.

If you have no idea about a new process, then use the self-tuning

program to optimize the PID values by selecting YES for SELF

to enable the self-tuning program. See section 3-18 for a descrip-

tion of the self-tuning program. You can use the auto-tuning pro-

gram for the new process or directly set the appropriate values

for PB1, TI1, and TD1 according to the historical records for the

repeated systems. If the control behavior is still inadequate, then

use manual tuning to improve the control. See section 3-20 for

more information on manual tuning.

CPB Programming: The cooling proportional band is measured

by % of PB with a range of 1~255. Initially set 100% for CPB

and examine the cooling effect. If the cooling action should be

enhanced then decrease CPB, if the cooling action is too strong

then increase CPB. The value of CPB is related to PB and its

value remains unchanged throughout the self-tuning and auto-

tuning procedures.

Adjustment of CPB is related to the cooling media used. If air is

used as the cooling medium, set CPB at 100(%). If oil is used as

the cooling medium, set CPB at 125(%). If water is used as the

cooling medium, set CPB at 250(%).

DB Programming: Adjustment of DB is dependent on the sys-

tem requirements. If a higher positive value of DB (greater dead

band) is used, unwanted cooling action can be avoided, but an

excessive overshoot over the set point may occur. If a lower neg-

ative value of DB (greater overlap) is used, an excessive over-

shoot over the set point can be minimized, but an unwanted cool-

ing action may occur. It is adjustable in the range -36.0% to

36.0% of PB1 (or PB2 if PB2 is selected). A negative DB value

shows an overlap area over which both outputs are active. A pos-

itive DB value shows a dead band

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