Fisher FIELDVUE DVC6200f Instruction Manual page 129

Instruction Manual
D103412X012
α:
fixed smoothing factor of 0.1 applied to RATE
F: feedforward control contribution from the feedforward input (FF_VAL)
E: error between setpoint and process variable
To further customize the block for use in your application, you can configure filtering, feedforward inputs, tracking
inputs, setpoint and output limiting, PID equation structures, and block output action. Table 4‐32 lists the PID block
parameters and their descriptions, units of measure, and index numbers, and figure 4‐10 illustrates the internal
components of the PID function block.
Figure 4‐10. PID Function Block Schematic
FF VAL
BKCAL IN
TRK IN D
RCAS IN
CAS IN
Operator
Setpoint
IN
TRK VAL
B2721
FF GAIN
FF SCALE
Feedforward
Calculation
MODE
RCAS OUT
Setpoint
Limiting
PID
Equation
SP HI LIM
SP LO LIM
SP RATE DN
SP RATE UP
Scaling
and
Filtering
HI HI LIM
HI LIM
DV HI LIM
DV LO LIM
PV SCALE
LO LIM
PV FILTER
LO LO LIM
Convert
TRK SCALE
OUT SCALE
ROUT IN
GAIN
OUT HI LIM
RATE
OUT LO LIM
RESET
OUT SCALE
Alarm
Operator
Detection
Output
Detailed Setup—PID Function Block
BKCAL OUT
ROUT OUT
Output OUT
Limiting
July 2013
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