Instruction Manual

Instruction Manual
D103434X012
Blocks
November 2014
86
parameters and their descriptions, units of measure, and index numbers, and figure B‐5 illustrates the internal
components of the PID function block.
Figure B‐5. PID Function Block Schematic
B2721
FF VAL
Alarm
Detection
Operator
Output
PID
Equation
Setpoint
Limiting
Feedforward
Calculation
BKCAL
OUT
OUT
RCAS
OUT
FF GAIN
FF
SCALE
PV
SCALE
PV
FILTER
SP
HI LIM
SP
LO LIM
SP
RATE DN
SP
RATE UP
Output
Limiting
MODE
BKCAL
IN
TRK
IN D
CAS
IN
IN
TRK
VAL
RCAS
IN
Scaling
and
Filtering
TRK
SCALE
OUT
SCALE
Convert
ROUT
OUT
ROUT
IN
OUT
HI LIM
OUT
LO LIM
OUT
SCALE
HI
HI LIM
HI
LIM
DV
HI LIM
DV
LO LIM
LO
LIM
LO
LO LIM
Operator
Setpoint
GAIN
RATE
RESET
Modes
The PID function block supports the following modes:
D Manual (Man)—The block output (OUT [9]) may be set manually.
D Automatic (Auto)—The SP [8] may be set manually and the block algorithm calculates OUT [9].
D Cascade (Cas)—The SP [8] is calculated in another block and is provided to the PID block through the CAS_IN [18]
connection.
D RemoteCascade (RCas)—The SP [8] is provided by a host computer that writes to the RCAS_IN [32] parameter.