Rockwell Automation 1769-OF4VI Compact I/O Isolated Analog Modules - Manual (Page 9)

1 Publication 1769-UM014B-EN-P - May 2010
Chapter
1
Overview
This chapter explains how analog data is used, describes the 1769-IF4I isolated
analog input module, and describes the 1769-OF4CI and 1769-OF4VI isolated
analog output modules. Included is information about:
 the use of analog I/O.
 the modules’ hardware and diagnostic features.
 an overview of the 1769 analog input system operation.
 an overview of the 1769 analog output system operation.
How to Use Analog I/O Data
Analog refers to the representation of numerical quantities by the
measurement of continuous physical variables. Analog applications are present
in many forms. The following application shows a typical use of analog data.
In this application, the controller controls the amount of fluid in a holding
tank by adjusting the valve opening. The valve is initially open 100%. As the
fluid level in the tank approaches the preset point, the controller modifies the
output to close the valve 90%, 80%, and so on, continuously adjusting the
valve to maintain the fluid level.
Figure 1.1 Analog I/O Application Example
Controller
Analog I/O
Module
Valve
Level Sensor
Analog Input Wired
to Tank
Analog Output
Wired to Valve