Example Pid Algorithm Listings; Pida Algorithm - VXI VT1422A User Manual

PIDA Algorithm

Setpoint +
Variable
Appendix G

Example PID Algorithm Listings

This appendix includes listings of the built-in PIDA and PIDB, as well as the
more advanced PIDC which can be downloaded as a custom algorithm.
• PIDA Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 491
• PIDB Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 493
• PIDC Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 500
Figure G-1 shows the block diagram of the PIDA algorithm.
P_factor
Variable
Σ
Error I_factor
variable
Variable
-
D_factor
Variable
Figure G-1. The Simple PID Algorithm "PIDA"
PIDA algorithm implements the classic PID controller. This implementation
was designed to be fast. In order to be fast, this algorithm provides no
clipping limit, alarm limits, status management or CVT/FIFO
communication (History Modes). The algorithm performs the following
calculations each time it is executed:
Error = Setpoint - <inp_chan>
I_out = I_out + I_factor * Error
<outp_chan> = P_factor * Error + I_out + D_factor * (Error - Error_old)
Error_old = Error.
+
<outp_chan>
Σ
I_out
+
variable
+
Example PID Algorithm Listings
Appendix G
process
channel
<inp_chan>
channel
491