Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 61)

Installing the Assembly
Chapter 6
6Ć11
This is a simplified diagram to give you an overall view of how you are to
connect these terminals. We give you further details in the following
sections and their associated figures. For all connections to the terminals,
limit the cable length to 50 feet.
Keep low-level conductors separate from high-level conductors. This is
particularly important for cable connections to the encoder. Follow the
practices outlined in the PC Grounding and Wiring Guidelines
(publication 1770-980).
Power Supplies
Use shielded cable for connecting the input power supply and the analog
power supply. Route these cables only with low-level conductors. Keep
these power supply cables as short as possible. Ground the common
terminal for each of these power supplies.
Encoder and Tachometer
For an encoder or tachometer connection, use only a single, continuous,
shielded cable segment. Do not break the cable for connection in a
junction box. Connect the cable directly from the encoder to the 1771-ES
expander.
Important: Ensure that the power supply for the encoder provides the
voltage recommended by the encoder manufacturers.
Shielded Cables
For many connections, we tell you to use shielded cable. Using shielded
cables and properly connecting their shields to ground protects against
electromagnetic noise interfering with the signals transmitted through the
cables.
WARNING:Use shielded cable where we tell you to use it and
how we tell you to use it. If you do not, the axis motion in your
positioning system could be unpredictable; this could result in
damage to equipment and/or injury to personnel.