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 o
p
eration executes at no.0
p
arameter
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.