B&B Electronics DELTA Temperature Controller DTB Series - Manual (Page 6)

5
7 Dual Loop Output Control (Heating / Cooling Control)
OFF PV
Set point
ON
Heating
Dead band
Heating hysteresis
Figure 1. Output
during dual loop output control
operation of ON/OFF control
Cooling hysteresis
Cooling
PV
0
Output
Dead band: dead
band width=positive
Set point
Heating Cooling
Figure 2. PID Dead Band is positive control,
Temperature control can be achieved either by heating or cooling. In DTB series, heating and
cooling can be operated simultaneously (Dual Loop output control) to perform temperature
control. When Dual Loop output control are used, two control outputs must be connected to the
heating and cooling devices. Please refer to the following for the operation:
: This parameter is used to select heating or cooling action if operate either heating or
cooling function in this controller. When selecting , 1st output group is heating (reverse)
control, and when selecting , 1st output group is cooling (forward) control. At this
moment, 2nd output group is regarded as an alarm output. If user select or , it
indicates that user can operate Dual Loop output control function in this controller. When
selecting
, 1st output group is heating (reverse) control and 2nd output group is cooling
(forward) control. When selecting , 1st output group is cooling (forward) control and 2nd
output group is heating (reverse) control.
In DTB series, P (Proportional Band), I(Integral Time) and D(Derivative Time) parameters are
automatically set by using the Auto-tuning (AT) function.
: This parameter is for the control mode that must be Dual Loop output control with PID
control method configured. The value of P, I and D of 1st output group can be set immediately.
The P value of 2nd output group is equal to (P value of 1st output group) x
and the
value of I and D of 2nd output group are the same as the value of I and D of 1st output group.
: Dead Band, shown as the following figure 1, 2 and 3. This parameter sets an area in
which the heating and cooling control output is 0 centering around the set point in a Dual Loop
output control mode.
:
Settings lock. To avoid incorrect operation, two key lock functions are provided.
: Lock 1 can lock all settings. All parameters and temperature settings can be locked to
disable changes. : Lock 2 can lock settings except the SV (Set point) value. All
parameters and temperature settings can be locked with the exception of the SV value. Press
and key simultaneously, the “Lock” status can be released.
PV
0
Output Dead band: dead
band width=negative
Set point
Heating Cooling
Figure 3. PID Dead Band is negative control,