7
Dual Loop Output Control (Heating / Cooling 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
: 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.
| Dead band |
Heating hysteresis | Cooling hysteresis |
ON |
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Heating | Cooling |
OFF | PV |
| Set point |
Figure 1. Output operation of ON/OFF control
during dual loop output control
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Figure 2. PID control, Dead Band is positive | |||||||||||||
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Set point
Figure 3. PID control, Dead Band is negative
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