Owner's manual

Section
3-1
3 Analog Output (AO)
Function Block
The Analog Output (AO) function block assigns an output value to a
field device through a specified I/O channel. The block supports mode
control, signal status calculation, and simulation. Figure 3-1 illustrates
the internal components of the AO function block, and Table 3-1 lists the
definitions of the system parameters.
TABLE 3-1. Analog Output Function
Block System Parameters
.
CAS_IN = The remote setpoint value from another
function block.
BKCAL_OUT = The value and status required by the
BKCAL_IN input of another block to
prevent reset windup and to provide
bumpless transfer to closed loop control.
OUT = The block output and status.
fieldbus-fbus_32a
AO
BKCAL_OUT
OUT
CAS_IN
Parameters Units Description
BKCAL_OUT EU of PV_SCALE The value and status required by the BKCAL_IN input of
another block to prevent reset windup and to provide
bumpless transfer to closed loop control.
BLOCK_ERR None The summary of active error conditions associated with the
block. The block errors for the Analog Output block areSimulate
Active, Input Failure/Process Variable has
Bad Status,
Output Failure, Read back Failed,andOut of Service.
CAS_IN EU of PV_SCALE The remote setpoint value from another function block.
IO_OPTS None Allows you to select how the I/O signals are processed. The
supported I/O options for the AO function block are SP_PV
Track in Man, Increase to Close,andUse PV for
BKCAL_OUT.
CHANNEL None Defines the output that drives the field device.
MODE None Enumerated attribute used to request and show the source of
the setpoint and/or output used by the block.
OUT EU of XD_SCALE The primary value and status calculated by the block in Auto
mode. OUT may be set manually in Man mode.
PV EU of PV_SCALE The process variable used in block execution. This value is
converted from READBACK to show the actuator position in
the same units as the setpoint value.
PV_SCALE None The high and low scale values, the engineering units code,
and the number of digits to the right of the decimal point
associated with the PV.