Cable recommendations, Shield connection – Rockwell Automation 1771-SF1 SERVO INT MOD User Manual
Page 7

Component Interfacing, Module
Preparation, and Installation
Chapter 2
2Ć3
Figure 2.1
Typical Connection Diagram
Not Used
10401
Servo Interface
Module
Field Wiring Arm
Full
Quadrature
Encoder
TTL
Differential
Line
Driver
Servo
Amplifier
Drive Current Inhibit
Amplifier On/Off
Analog Control, + 10V
Channel A
Channel A
Channel B
Channel B
Marker
Marker
1
2
3
4
5
6
7
8
9
10
11
12
The cable distance between the servo interface module and the differential
line drivers should not exceed 40 feet. Use a twisted conductor pair
within a shielded braid (Belden #8761 or equivalent) for connections to
the line drivers. Use a 14 gauge conductor for the analog output to the
servo amplifier and make this connection as short as possible to minimize
the voltage drop in the cable.
Belden 8761 or equivalent cable has a foil shield with a bare stranded
drain wire. The shield should be connected to earth ground at one end of
the cable only. This can be at the customer end of the cable or at an I/O
chassis mounting bolt or stud. At the other end of the cable, the shield
should be cut short and taped back to insulate it from any electrical
contact. This is to guard against unwanted radiated electrical noise and
ground current loops.
Cable Recommendations
Shield Connection