Chapter 15. The PID functions
15-23
3) A/D module setting
a) Channel setting
: use channel 0
b) Output data type
: – 48 ~ 4047
c) Input p rocessing
: Sampling
4) D/A module setting
a) Channel setting
: use channel 0
15.4.3 Program description
15.4.3.1
Use only PID operation (without A/T function)
1) Convert the measured temperature (0 ~ 250
°
C) to current signal (4 ~ 20mA), and
input the current signal to the channel 0 of A/D module. Then, the A/D module
converts the analog signal to digital value (0 ~ 4000)
2) PID6CAL function block will calculate manipulate value (MV : 0 ~ 4000) based on
PID parameter settings (P_GAIN, I_TIME, D_TIME, etc.) and PV from A/D module.
Then, the calculated MV is output to the channel 0 of D/A module.
3) D/A module will convert the MV (0 ~ 4000) to analog signal (4 ~ 20mA) and output
to the actuator (power converter).
15.4.3.2
Use PID operation with A/T function
1) Convert the measured temperature (0 ~ 250
°
C) to current signal (4 ~ 20mA), and
input the current signal to the channel 0 of A/D module. Then, the A/D module
converts the analog signal to digital value (0 ~ 4000)
2) A/T function block will calculate manipulate value (MV : 0 ~ 4000) based on the SV
and PV from A/D module. Simultaneously, the A/T module will calculate P,I and D
parameters.
3) The END output of A/T module will be 1 when the A/T operation is completed. Then,
PID module will start operation with PID parameters that are calculated by A/T
module.
4) D/A module will convert the MV (0 ~ 4000) to analog signal (4 ~ 20mA) and output
to the actuator (power converter).
