Analog Input Function Blocks 1 And 2; Aifb Function Groups; How Aifbs Work - Siemens SITRANS LR460 Operating Instructions Manual

PROFIBUS PA profile structure
E.5 Analog input function blocks 1 and 2
E.5

Analog input function blocks 1 and 2

There are two identical Analog Input Function Blocks which operate independently. The
figure below shows how measured values are processed within the Analog Input Function
Block (AIFB 1 or AIFB 2) to produce the device output, which is communicated via cyclic
transfer to PROFIBUS PA, and displayed on the LCD.
E.6

AIFB function groups

E.7

How 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 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.
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Operating Instructions, 10/2021, A5E42035355-AB
SITRANS LR460