Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 39)

Publication GMC-RM001A-EN-P — July 2001
Segregating Sources and Victims 3-7
Data/Communications Cables
Data and communication cables that come from a remote structure
(refer to the chapter High Frequency (HF) Bonding) will carry noise
on their shields. Follow the guidelines listed below when installing
data or communication cables.
• Follow the product manual recommendations for termination
resistors, minimum and maximum length, etc.
• Carefully segregate data and communication cables from dirty and
especially very-dirty cables.
• Ground shields to the panel at the point of entry when permitted.
Check your manual for the recommended procedure. Connecting
to the 360° shield is preferable to the use of pigtails. If pigtails
must be used, they should be kept short. Refer to the section
Grounding Cable Shields in Appendix A for more information on
grounding cable shields.
• Refer to the chapter Filtering Noise for more information.
Proximity Switches (except
registration) X
Photoelectric Cell X
24V dc Relay X
Transformer Indicator Lamp X
Data/Communications
4 X X X
Encoder/Resolver X X
Logic circuit power X X
High Speed Registration inputs
5 X X
PLC Analog I/O X X
PLC High Speed Counter input X X
1
An X in this column indicates a ferrite sleeve fitted to the wire is recommended.
2
An X in this column indicates a shielded cable is recommended.
3 Keep unshielded conductors as short as possible and separated from dirty and clean cables as far as possible.
4
Refer to the section Data/Communications Cables below for more information.
5
Refer to the chapter High Speed Registration Inputs for more information.
Note: Grounding power cable shields at entry to the cabinet is recommended.
Cable and Wire Category
Zone Method
Very-
Dirty Dirty Clean Ferrite
Sleeve
1
Shielded
Cable
2