Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 77)

Publication GMC-RM001A-EN-P — July 2001
Chapter
9
High Speed Registration Inputs
Chapter Objectives This chapter describes how wiring, sensitive to electrical noise,
benefits from proper noise reduction strategies. This chapter covers
the following topics:
• Understanding registration inputs
• Noise reduction methods
• Power supply wiring options
• Signal noise filter options
• Registration error
Understanding Registration
Inputs High speed registration inputs are potentially sensitive to noise by
design. Typically, the specification states that the input responds
within 1 microsecond of the signal going high, while in practice, the
response is often even faster. Noise pulses of this duration are
common in a typical drive system.
IMPORTANT
Coupling is usually capacitive if unshielded cable is
run near noisy cables or if voltage differentials exist
between the detector mounting and the equipment
carrying the registration input. For these reasons,
treat high speed registration input circuits with
special care.