Owner's manual
Table Of Contents
- Foundation™ Fieldbus Blocks
- Foundation™ Fieldbus Technology and Fieldbus FunctionBlocks
- Analog Input (AI) FunctionBlock
- Analog Output (AO) Function Block
- Arithmetic Function Block
- Discrete Input (DI) Function Block
- Discrete Output (DO) Function Block
- Integrator (INT) FunctionBlock
- Input Selector (ISEL) FunctionBlock
- Proportional/Integral/Derivative (PID) Function Block
- Signal Characterizer (SGCR) Function Block
- Diagnostics (ADB) Transducer Block
- Applications
- Analog input (AI) Function Block
- Analog Output (AO) Function Block
- Arithmetic (ARTH) Function Block
- Discrete Input (DI) Function Block
- Discrete Output (DO) Function Block
- Input Selector (ISEL) Function Block
- Integrator (INT) Function Block
- Proportional/ Integral/Derivative (PID) Function Block
- Signal Characterizer (SGCR) Function Block
- Index
FOUNDATION
TM
Fieldbus Blocks Manual
3-2
Setting the Output To set the output for the AO block, you must first set the mode to define
the manner in which the block determines its setpoint. In Manual mode
the value of the output attribute (OUT) must be set manually by the
user, and is independent of the setpoint. In Automatic mode, OUT is set
automatically based on the value specified by the setpoint (SP) in
engineering units and the I/O options attribute (IO_OPTS). In addition,
you can limit the SP value and the rate at which a change in the SP is
passed to OUT.
In Cascade mode, the cascade input connection (CAS_IN) is used to
update the SP. The back calculation output (BKCAL_OUT) is wired to
the back calculation input (BKCAL_IN) of the upstream block that
provides CAS_IN. This provides bumpless transfer on mode changes
and windup protection in the upstream block. The OUT attribute or an
analog readback value, such as valve position, is shown by the process
value (PV) attribute in engineering units.
To support testing, you can enable simulation, which allows you to
manually set the channel feedback. There is no alarm detection in the
AO function block.
To select the manner of processing the SP and the channel output value
configure the setpoint limiting options, the tracking options, and the
conversion and status calculations.
READBACK EU of XD_SCALE The measured or implied actuator position associated with the
OUT value.
SIMULATE EU of XD_SCALE Enables simulation and allows you to enter an input value
and status.
SP EU of PV_SCALE The target block output value (setpoint).
SP_HI_LIM EU of PV_SCALE The highest setpoint value allowed.
SP_LO_LIM EU of PV_SCALE The lowest setpoint value allowed.
SP_RATE_DN EU of PV_SCALE
per second
Ramp rate for downward setpoint changes. When the ramp
rateissettozero,thesetpointisusedimmediately.
SP_RATE_UP EU of PV_SCALE
per second
Ramp rate for upward setpoint changes. When the ramp rate
is set to zero, the setpoint is used immediately.
SP_WRK EU of PV_SCALE The working setpoint of the block. It is the result of setpoint
rate-of-change limiting. The value is converted to percent to
obtain the block’s OUT value.
Parameters Units Description