Rockwell Automation 1756-OF8I ControlLogix Eight-channel Isolated Analog I/O Modules - Manual (Page 59)

Rockwell Automation Publication 1756-UM540A-EN-P - May 2014 59
1756-IF8I Isolated Analog Input Module Chapter 3
Field-side Circuit Diagrams
The following diagrams show the field-side circuitry for the 1756-IF8I module.
Figure 6 - 1756-IF8I Module Field-side Circuit with Voltage Input
Figure 7 - 1756-IF8I Input Module Field-side Circuit with an Externally-powered Current
Input Loop
RTN-x
1
μ
A
Pullup
0.1
μ
F
IN_x/V
A/D Converter
7500
Ω
2.5V Vref
+
IN_x/I/SRC
1000
Ω
55
Ω
0.01
μ
F 0.01
μ
F
–
1000
Ω
20
Ω
Voltage
Source
0.01
μ
F
0.01
μ
F
PGA
RTN-x
0.1
μ
F
IN_x/V
A/D Converter
7500
Ω
IN_x/I/SRC
1000
Ω
55
Ω
4…20 mA
Transmitter
0.01
μ
F 0.01
μ
F
1000
Ω
20
Ω
Transmitter
Power
0.01
μ
F
0.01
μ
F
Current Limit
24.9
Ω
25
Ω
i_sense
2.5V Vref
PGA
+
–
+
–