Siemens Sitrans LR250 Operating Instructions Manual page 149

AIFB function groups
USER-selected
Simulation ON/OFF
SIMULATION
enable
simulate
value and
AIFB INPUT:
status
Process
Variable from
TB
Value
Status
Analog Input Function Block function groups (simulation, mode and status)
Measured values are processed within an Analog Input Function Block to produce the
device output (see
cyclic transfer to PROFIBUS PA and displayed on the LCD.
How an Analog Input Function Block works
The AIFB provides a linear conversion to any desired units.
1) The AIFB Input value is the processed output value of the Transducer Block, in
Transducer Block units.
2) The user selects the desired AIFB output units and scaling is applied.
3) Damping may be applied based on a time constant provided by the user (see
Damping
on page 128 for details).
4) The status of the input value from the Transducer Block is checked. If the status is
Bad, a Fail-safe condition occurs. The output is determined by the setting for Fail-
safe Mode.
5) Mode (2.6.2.) allows the entire AI block to be overridden by a Manual Output value.
See Mode (2.6.2.) on page 83 for details.
7ML19985JF04 SITRANS LR250 (PROFIBUS PA) – OPERATING INSTRUCTIONS
OUTPUT
SCALING
Value
ON
MODE
and
OFF Status
STATUS
handling
AIFB function groups
Output range:
USER-selected
Target Mode
OUT
Manual
Out of Service
Fail-
safe
AUTO
on page 143). The output is communicated via
AIFB
Out
(AIFB Output)
Alarm
OUT VALUE
Limit
Value
Check
Status
straight to LCD
(same values
displayed on LCD
as PLC)
Page 143