Figure 3 - Digital Value; Figure 4 - Process In Plc - Honeywell 2MLF-AV8A User Manual

1. Introduction
1.3. Terminology
can be displayed as 0 and 1, respectively, in a digital system. This is called as the binary
numbering system. Decimals stored in binary numbering systems are called binary coded
decimals (BCD). Figure 3 displays the digital value of the physical parameter.
As the PLC processes only binary numbers, analog values cannot be directly input to the
PLC's CPU for calculation. Conversion from analog to digital (as shown in Figure 4) is
required. This is done using Analog to Digital converter (A/D conversion module).
Similarly, to get an analog output from a digital value, a Digital to Analog converter
(D/A conversion module) is used.
18 Analog Input Module 2MLF-AV8A, AC8A User's Guide
Figure 3 – Digital value
Figure 4 – Process in PLC
Honeywell
R200
September 2010