AO Function Block
December 2009
4-73
B2718-1 / IL
CAS_IN, 2
OUT
SP
Time
Figure 4-10. Analog Output Function Block Timing Diagram
SP RATE UP
SP RATE DN
1 second 1 second 1 second 1 second
1 macrocycle
1 macrocycle
TRANSDUCER BLOCK
TRAVEL TARGET
FSTATE_TIME [23] elapses and the fault condition
has not cleared.
I/O Options
The I/O options parameter (IO_OPTS [14]) allows you
to select how the I/O signals are processed. You can
set I/O options in Out of Service mode only. The
following I/O options are available in the AO block:
Use PV for BKCAL_OUT—Changes the
BKCAL_OUT [25] value to the PV [7] value. When the
Use PV for BKCAL_OUT option is not enabled
(False), the BKCAL_OUT [25] value is the working
setpoint value.
Target to Man if Fault State Activated—Set the
target mode to Man, thus losing the original target, if
Fault State is activated. This latches an output block
into the manual mode.
Use Fault State value on Restart—Use the value of
FSTATE_VAL [24] for SP [8] when power is restored
or if the device is restarted, otherwise use the last
value saved in non-volatile memory. This does not act
like Fault State, it only uses the value of
FSTATE_VAL [24].
Fault State to Value—The output action to take when
a fault occurs (if not selected, use hold last value; if
selected, use FSTATE_VAL [24]).
Increase to Close—If the Increase to Close bit is set
the value to the transducer is inverted, e.g. 20%
becomes 80%.
SP−PV Track in Man—Permits the setpoint to track
the process variable when the target mode of the
block is MAN.
SP−PV Track in LO or IMan—Permits the setpoint to
track the process variable when the actual mode of
the block is LO or IMan.
SP Track retained Target—Permits the setpoint to
track the RCas or Cas parameter based on the
retained target mode when the actual mode of the
block is LO or Man. When SP-PV track options are
enabled, the SP Track retained target will have
precedence in the selection of the value to track when
the actual mode is Man and LO.
Simulation
When simulate is active, the transducer
sub-parameters show the actual transducer block
status and value as normally passed back to the AO
block. The Simulate sub-parameters are writable and
replace actual transducer values.
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