Control Output; Pid Control Parameters - GE FVP110 Maintenance Manual

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In Cas mode
Where:
ΔMV = change in control output
n
ΔPV
= change in measured (controlled) value
n
= PV - PV
n
ΔT = control period = period_of_execution in block header
K = proportional gain = GAIN (= 100/proportional band)
TI = integral time = RESET
TD = derivative time = RATE
The subscripts, n and n-1, represent the sampling time and thus PV
PV value sampled most recently and the PV value sampled at the preceding control
period respectively.
Table 47 shows the PID control parameters.
Parameter
GAIN
RESET
RATE

Control Output

The final control output value, OUT, is computed based on the change in control output
ΔMVn, which is calculated at each control period in accordance with the aforementioned
algorithm. The PID block performs the velocity type output action for the control output by
determining the value of the new control output (OUT) by adding the change in control
output calculated in the current control period, ΔMV
the MV(OUT), MVRB (BKCAL_IN). This action can be expressed as:
OUT = BKCAL_IN - ΔMV
ΔMV = ΔMV
n'
n-1
Table 47 PID Control Parameters
Description
Proportional gain
Integral time
Derivative time
n'
which is scaled by PV_SCALE and OUT_SCALE
n
FVP 110 Fieldbus Valve Positioner Manual
0.1 to 10,000 (seconds)
, to the current read-back value of
n
160
and PV denote the
n n-1
Valid Range
0.05 to 20
0 to infinity