May 2016
Reference Manual
00809-0100-4530, Rev DD
363
Appendix I
Analog-Input Block
Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 366
Damping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 367
Signal Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 367
Block Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 369
Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 369
Alarm Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 370
Advanced Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 371
Configure the AI Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 372
Figure I-1. Analog-Input Block
The Analog Input (AI) function block processes field device measurements and makes them
available to other function blocks. The output value from the AI block is in engineering units
and contains a status indicating the quality of the measurement. The measuring device may
have several measurements or derived values available in different channels. Use the
channel number to define the variable that the AI block processes.
The AI block supports alarming, signal scaling, signal filtering, signal status calculation,
mode control, and simulation. In Automatic mode, the block’s output parameter (OUT)
reflects the process variable (PV) value and status. In Manual mode, OUT may be set
manually. The Manual mode is reflected on the output status. A discrete output (OUT_D) is
provided to indicate whether a selected alarm condition is active. Alarm detection is based
on the OUT value and user specified alarm limits.
illustrates the
internal components of the AI function block, and Table I-1 lists the AI block parameters and
their units of measure, descriptions, and index numbers.
OUT = The block output value and status
OUT_D = Discrete output that signals a selected alarm condition
OUT_D
AI
OUT