Instruction Manual

Instruction Manual
D103434X012
Blocks
November 2014
114
Figure B‐11. Analog Output Function Block Schematic
B2717
CAS IN
Position
Feedback
Analog
Output
Access
Analog
Output
Access
Analog
Input
Shed
Mode
SP
HI/LO
Limit
SP
Rate
Limit
Convert
and Status
Calculatio
n
BKCAL
OUT
OUT
RCAS
OUT
RCAS
IN
SP
RATE DN
SP
RATE UP
SP
WRK
PV
SCALE
IO
OPTS
Operator
Setpoint
READ
BACK
PV
SP
LOW LIM
SP
HI LIM
CHANNEL
MODE
D RemoteCascade (RCas)—The SP [8] is set by a host computer by writing to the RCAS_IN [28] parameter. The SP [8]
value is used to set the OUT [9] attribute automatically.
D Out of Service (OOS)—The block is not processed. The output channel is maintained at the last value and the status
of OUT [9] is set to Bad: Out of Service. The BLOCK_ERR [6] attribute shows Out of Service.
D Initialization Manual (Iman)—The path to the output hardware is broken and the AO block output will remain at the
last position. This means the transducer block mode is Out of Service or Manual or configured to respond to the DO
block.
D Local Override (LO)—The output of the block is not responding to inputs because the fault state action is active. OUT
[9] freezes or goes to value per IO_OPTS [14].
The target mode of the block may be restricted to one or more of the following modes: Man, Auto, Cas, RCas, or OOS.
Mode Handling
Shed Options—RCAS Mode Only
Automatically changing through the permitted modes when starting from a remote mode, fall from (or shed) or climb
to a remote mode is determined by the parameter SHED_OPT [27]. A block climbs and sheds through the same path.
For example, if SHED_OPT [27] 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.