Chapter 7 Usage of Various Functions
7-35
e) Program
Explanation
•
When the input condition M0 turns on, PID operation executes at no.0 parameter.
•
PID execution status registrate D0000 and the output value of control result registrate D0001
•
If SV Ramp is designated, current SV is registrate D0005
•
D/A module converts the MV to analog signal and output to the actuator (power converter).
•
When the input condition M0 turns off, output 0 to the D/A conversion module.
(3) In case of using combined function of PID operation and Auto tuning.
a) PID operation explanation (with A/T function)
•
Measure current temperature (-200~600
°
C) by RTD module then digital conversion value(0 ~ 4000) is stored to
D4780
•
PID8AT instruction will calculate manipulate value (MV : 0 ~ 4000) based on the SV and PV from RTD module.
Simultaneously, the PID8AT instruction will calculate P,I and D parameters.
•
The END bit of auto tuning status device will be 1 when the auto tuning is completed. Then, MASTER-K120S
will start PID operation with PID parameters that are calculated by A/T module.
b) Auto tuning parameters
•
Scan time : S_TIME=5 (sampling time = 0.5 seconds)
•
SV setting : 1300(60
°
C ), 1350(70
°
C ),1400(80
°
C ),1500(100
°
C)
•
Current value setting : D4780(Digital value of RTD module Ch0)
•
Identification method setting : Select PRC Method
When M0 turns on,
PID operation executes at no.0 parameter
When M0 turns off,
CPU stop PID operation and output 0 to D/A module
The manipulated value is out to D/A module
When selected, the scan time
fixed to 1 sec.