Siemens SITRANS LR200 Instruction Manual page 79

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.
Failsafe
• 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.
Device / Output Simulation
One of three settings can be selected:
Setting
AUTO automatic
MAN manual
O/S function block disabled
• The result is the output parameter (OUT).
AIFB execution steps:
The AIFBs can provide a linear conversion to any desired units.
1. The input value is normalized (Scaling Input)
Process Variable range applies to any of the four LTB values. (Units of the Process
Variable scale are the same as the units used for the LTB output.) Output units
together with Process Variable range determine how the LTB output is converted to
whatever units the customer wants.
7ML19985HP01 SITRANS LR 200 (PROFIBUS PA) – INSTRUCTION MANUAL
description Output value
the automatically-recorded measured value
a manually-set fixed simulation value
the preset safety value.
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