Rockwell Automation 1769-HSC Compact High Speed Counter Module - Manual (Page 55)

Rockwell Automation Publication 1769-UM006E-EN-P - July 2013 55
Installation and Wiring Chapter 3
Considerations for Reducing Noise
In high-noise environments, the 1769-HSC module inputs can accept ‘false’
pulses, particularly when using low frequency input signals with slowly sloping
pulse edges. To minimize the effects of high frequency noise on low frequency
signals, perform the following:
• Identify and remove noise sources.
• Route input cabling away from noise sources.
• Use your programming software to select low-pass filters on input signals.
Filter values depend on the application and can be determined empirically.
• Use devices which output differential signals, such as differential encoders,
to minimize the possibility that a noise source will cause a false input.
Remove and Replace the Terminal Block
When wiring the module, you do not have to
remove the terminal block. If you remove the
terminal block, use the write-on label on the side of
the terminal block to identify the module location
and type.
To remove the terminal block, loosen the upper- and lower-retaining screws. The
terminal block will back away from the module as you remove the screws. When
replacing the terminal block, torque the retaining screws to 0.46 N•m (4.1 lb•in).
Wire the Finger-safe Terminal Block
When wiring the terminal block, keep the finger-safe cover in place.
SLOT # _____
MODULE TYPE ______
Wiring the
Finger-safe
Terminal Block
Upper Retaining Screw
Lower Retaining Screw