Emerson Rosemount 2240S, Справочное руководство, Страница: 77 / 194

67
Reference Manual
00809-0100-2240, Rev DA
Configuration/Operation
October 2017
Configuration/Operation
Analog Input block
Figure 5-12. 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 and passes on to linked blocks. For further information refer to
“Analog input block” on
page 161 and “Analog Input block” on page 73 .
Multiple Analog Input block
The Multiple Analog Input (MAI) block makes the temperature elements available to other function
blocks.
PID block
The PID function block combines all of the necessary logic to perform proportional/integral/derivative
(PID) control. The block supports mode control, signal scaling and limiting, feed forward control,
override tracking, alarm limit detection, and signal status propagation.
The block supports two forms of the PID equation: Standard and Series. You can choose the appropriate
equation using the MATHFORM parameter. The Standard ISA PID equation is the default selection.
Input Selector block
The Input Selector (ISEL) function block can be used to select the first good, Hot Backup, maximum,
minimum, or average of as many as eight input values and place it at the output. The block supports
signal status propagation.
Integrator block
The Integrator (INT) function block integrates one or two variables over time.
This block will accept up to two inputs, has six options how to totalize the inputs, and two trip outputs.
The block compares the integrated or accumulated value to pre-trip and trip limits and generates
discrete output signals when the limits are reached.
Arithmetic block
The Arithmetic (ARTH) function block provides the ability to configure a range extension function for a
primary input. It can also be used to compute nine different arithmetic functions.
OUT=The block output value and status
OUT_D=Discrete output that signals a selected
alarm condition
OUT_D
OUT
A