Rockwell Automation MPAR Electric Cylinders - Manual (Page 7)

MP-Series Electric Cylinders 7
Rockwell Automation Publication MPAR-IN001D-EN-P - September 2012
Preventing Electrical Noise
Electromagnetic interference (EMI), commonly called electrical noise, can reduce motor
performance. Effective techniques to counter EMI include filtering the AC power, using
shielded cables, separating signal cables from power wiring, and practicing good grounding
techniques.
Follow these guidelines to avoid the effects of EMI:
• Isolate the power transformers or install line filters on all AC input power lines.
• Physically separate signal cables from motor cabling and power wiring. Do not route
signal cables with motor and power wires, or over the vent openings of servo drives.
• Ground all equipment by using a single-point parallel ground system that employs
ground bus bars or large straps. If necessary, use additional electrical-noise reduction
techniques to reduce EMI in noisy environments.
Refer to System Design for Control of Electrical Noise Reference Manual, publication
GMC-RM001 , for additional information on reducing the effects of EMI.
Build and Route Cables
Knowledgeable cable routing and careful cable construction improves system electromagnetic
compatibility (EMC).
Follow these steps to build and install cables.
1. Keep wire lengths as short as physically possible.
2. Route signal cables (encoder, serial, analog) away from motor and power wiring.
3. Separate cables by 0.3 m (1 ft) minimum for every 9 m (30 ft) of parallel run.
4. Ground both ends of the encoder cable shield and twist the signal wire pairs to prevent
electromagnetic interference (EMI) from other equipment.
ATTENTION: High voltage can be present on the shield of a power cable if the shield is not
grounded.
Make sure there is a connection to ground for any power cable shield.
Failure to observe these safety precautions could result in personal injury or damage to equipment.