User's Manual

Page 116 SITRANS LR260 (PROFIBUS PA) – OPERATING INSTRUCTIONS A5E32337685
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F: Profile structure
If a temperature limit is exceeded, the status changes. Peak indicators
1)
allow you to
check the maximum and minimum temperatures that have occurred.
Analog Input Function Blocks 1 and 2
The figure below shows how measured values are processed within the two Analog
Input Function Blocks (AIFB1 and AIFB2) to produce the device outputs, which are
communicated via cyclic transfer to PROFIBUS PA, and displayed on the LCD.
Analog Input Function Block function groups (simulation, mode and status)
2)
How the AIFBs work
The Analog Input Function Blocks allow you to control modifications to the output value
(PROFIBUS cyclic data).
Output Conversion
Values transmitted by the Level TB have a status attached. The decision on what to do
with each value is made by the Analog Input Function Block.
Device/ Input Simulation
The input can be a simulated value instead of a TB OUT value. This allows the AI block to
be tested independently of the characteristics of the environment.
Fail-safe
If the status of the Primary Value or Simulation Value is bad, the fault logic can output
either the last usable measured value, or a given substitute value.
1)
Open the menu View – Peak Values.
2)
The output from the Level Transducer Block can be called the Primary Value (or
Secondary Value). When it becomes the input to the AIFB, it is called the Process
Variable.
enable
on
FB
algorithm
Status
OUT
AUTO
MODE and
STATUS
handling
Process Variable
2
from LTB
(Function Block
input)
Value
Status
Alarm
Limit
Check
Out of
Service
OUT
OUT
MAN
Value
simulate
value and
status
Value
Status
Operator
Operator
off
Simulate
Parameter
Fail-
safe