Dual Set Point / Pid - Brainchild BTC-2500 User Manual

5 9 Dual Set Point / PID

5 9 Dual Set Point / PID
The BTC-2500 will switch between the two PID sets based on the process The BTC-2500 will switch between the two PID sets based on the process
value, the set point or either of the event input. As the control ramps up to the value, the set point or either of the event input. As the control ramps up to the
higher process value, the process characteristics changes. As this happens, higher process value, the process characteristics changes. As this happens,
the original PID values are no longer valid. To achieve optimal control over the the original PID values are no longer valid. To achieve optimal control over the
entire range, a second PID set is used. entire range, a second PID set is used.
Example 1: Single Set Point / Dual PID Example 1: Single Set Point / Dual PID
A heat treating furnace is used over the range of 400 C to 1200 C. A heat treating furnace is used over the range of 400 C to 1200 C.
( 1 ) Set the following parameters in the Setup menu: ( 1 ) Set the following parameters in the Setup menu:
FUNC= FULL FUNC= FULL
A1FN= PV1H A1FN= PV1H
A1MD= NORM A1MD= NORM
EIFN= PID2 EIFN= PID2
PVMD= PV1 PVMD= PV1
SPMD= MINR SPMD= MINR
( 2 ) Adjust the following parameters in the User menu: ( 2 ) Adjust the following parameters in the User menu:
A1SP= 800 C A1SP= 800 C
A1HY= 1.0 C A1HY= 1.0 C
PL1= 100 ( % ) PL1= 100 ( % )
RAMP: According to the process requirement RAMP: According to the process requirement
SP1: According to the process requirement SP1: According to the process requirement
( 3 ) Tune first PID set at SP1= 500 C and tune second PID set at SP1=1100 C, ( 3 ) Tune first PID set at SP1= 500 C and tune second PID set at SP1=1100 C,
or set the proper values for PB1, TI1, TD1, PB2, TI2 and TD2 directly or set the proper values for PB1, TI1, TD1, PB2, TI2 and TD2 directly
according to the previous records to eliminate auto-tuning sequence. according to the previous records to eliminate auto-tuning sequence.
The circuit diagram and its temperature profile are shown as follows : The circuit diagram and its temperature profile are shown as follows :
1 2 3 4 5
8 9 10 11
C
800
PID Crossover Value PID Crossover Value
94
6 7
12 13 14
Alarm 1 controls Alarm 1 controls
Event input Event input
Process Value Process Value
To To
Furnace Furnace
Heater Heater
Use PID 1 Use PID 1
Use PID 2 Use PID 2
Time
UM25001C
AC power AC power
Figure 5.14 Figure 5.14
Dual PID Furnace Dual PID Furnace
Heater Heater
Power Power
Input Input
Figure 5.15 Figure 5.15
Dual PID Crossover Dual PID Crossover