Rockwell Automation Publication 750-IN100B-EN-P - July 2017 135
Chapter 6
I/O Wiring
Important points to remember about I/O wiring:
• Always use copper wire.
• Wire with an insulation rating of 600V or greater is recommended.
• Control and signal wires should be separated from power wires by at
least 0.3 meters (1 foot).
• For CE compliance, 115 volt digital input wiring must be shielded or
must not exceed 30 meters (98 feet) in length.
• In order to maintain electrical safety for all user-accessible low voltage
circuits (SELV and PELV circuits), I/O terminals designated for 24V or
lower voltage must not be connected to a circuit of higher voltage or a
circuit which is not adequately insulated from dangerous voltages with
double or reinforced insulation within other connected equipment or
wiring.
• In order to provide electrical safety for user-accessible low voltage I/O
circuits which are referenced to earth (PELV circuits) and which may be
touched simultaneously, care should be taken to provide a common
earth reference for all equipment connected to the drive.
IMPORTANT I/O terminals labeled ‘(–)’ or ‘Common’ are
not referenced to earth ground
and are designed to greatly reduce common mode interference. Grounding
these terminals can cause signal noise.
ATTENTION: Hazard of personal injury or equipment damage exists when
using bipolar input sources. Noise and drift in sensitive input circuits can
cause unpredictable changes in motor speed and direction. Use speed
command parameters to help reduce input source sensitivity.