Rockwell Automation 1769-IF4XOF2 Compact 8-Bit Low Resolution Analog I/O Combination Module - Manual (Page 16)

Publication 1769-UM008A-EN-P - November 2001
1-6 Overview
Module Operation
Module Block Diagram
The module’s input channel circuitry consists of four differential
analog inputs multiplexed into a single analog-to-digital (A/D)
converter. The A/D converter reads the selected input signal and
converts it to a digital value which is presented to the controller. The
multiplexer sequentially switches each input channel to the module’s
A/D converter. The module’s output channel uses a digital-to-analog
(D/A) converter to read the digital output data from the controller and
convert it to an analog output signal. See the block diagram below.
Module Calibration
The module’s input/output channel calibration is guaranteed by its
design. No field calibration is required.
Vin+
Vout+
Iout+
ANLG COM
Iin+
V/Iin-
CH0
CH0
CH1
CH1 CH2 CH3
A-GND
A-GND
A-GND
Vref VREF
AIN+
A/D
MCU
ASIC
VA3
VA2
VA3
VA2
VA2
VA2
VA1
VA3
VA1 VS1
VS1
VS2
TXD
RXD
A-GND
A-GND
S-GND
D/A
Input
(same as CH0)
Channel Select
DC/DC
Power
Supply
Galvanic
Isolation
Mu
lt
ip
le
xe
r
Bus
Output
(same as CH0)