Tempco TEC-2500, Instruction Manual

Page: 42 / 108

38
3–7 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 produce 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 3-9 and 3-10) 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, OUT2=AL2, A2FN=PV1.H, A2MD=NORM, 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 3-19 for a description of the self-
tuning program. You can use the auto-tuning program 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 3-21 for more
information on manual tuning.