Control Techniques Digitax ST - Page 178

Menu 14
Parameter
structure
Keypad and
display
Parameter x.00
Parameter
description format
Advanced parameter
descriptions
Serial comms
protocol
Electronic
nameplate
Performance
178 Digitax ST Advanced User Guide
www.controltechniques.com Issue Number: 1
Subject to the limits the PID controller output is given by
output = error x [P + I/s + Ds/(0.064s + 1)]
Where:
error = reference - feedback
P = proportional gain = Pr 14.10
I = integral gain = Pr 14.11
D = differential gain = Pr 14.12
Therefore with an error of 100% and P = 1.000 the output produced by the proportional term is 100%. With an error of 100% and I = 1.000 the output
produced by the integral term will increase linearly by 100% every second. With an error that is increasing by 100% per second and D = 1.000 the
output produced by the D term will be 100%.
This parameter defines the time taken for the reference input to ramp from 0 to 100.0% following a 0 to 100% step change in input.
14.01 PID output
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
21 1 1
Range ±100.00 %
Update rate 4ms write
14.02 PID main reference source
14.03 PID reference source
14.04 PID feedback source
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
2 1111
Range Pr 0.00 to Pr 21.51
Default Pr 0.00
Update rate Read on reset
14.05 PID reference source invert
14.06 PID feedback source invert
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Default 0
Update rate 4ms read
14.07 PID reference slew rate limit
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 111
Range 0.0 to 3,200.0 s
Default 0.0
Update rate Background read
14.08 PID enable
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Default 0
Update rate 4ms read
14.09 PID optional enable source
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
2 1111
Range Pr 0.00 to Pr 21.51
Default Pr 0.00
Update rate Read on reset