Emerson FIELDVUE DVC6200f, Instruction Manual

Page: 125 / 326

PID Function Block
November 2010 113
B2721 / IL
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
Figure 4-10. PID Function Block Schematic
You can configure the Man, Auto, Cas, and OOS
modes as permitted modes for operator entry.
Mode Handling
Shed Options—RCAS Mode Only
Shed from or climb to a remote mode is determined by
the parameter SHED_OPT [34]. A block climbs and
sheds through the same path. For example, if
SHED_OPT [34] specifies that a block should shed to
Auto, then, if the block target mode is set to RCas, the
block goes through Auto on the way to RCas. You can
configure the shed option as follows:
Shed With Return Options
Remote cascade or remote output connection failure
shifts actual mode but keeps trying to restore remote
cascade or remote output (in other words, the remote
cascade or remote output target mode stays in effect).
Normal—On failure of a remote connection, the block
attempts to attain the highest permitted non-remote
mode until the remote connection is restored. Cas is
the highest permitted non-remote mode and Auto is is
the next highest permitted non-remote mode. If Cas or
Auto are not available, the block will shed by default to
Man.
Retained Target—The retained target mode is the
mode the block was in before changing to one of the
remote target modes. On failure of a remote
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