Minimizing Electrical Noise On Analog Modules - Allen-Bradley SLC 500 1746-NI4 Installation Instruction

Once you have wired your analog module and properly labeled the terminal
block, install the terminal block on the analog module. To install the terminal
block:
1. Align the terminal block with the receptacle.
2. Insert the terminal block and press firmly at the top and bottom until it is
properly secured.
To remove the terminal block, grasp it on the top and bottom and pull outward
and down.
Minimizing Electrical Noise on Analog
Modules
Inputs on analog modules employ digital high frequency filters that significantly
reduce the effects of electrical noise on input signals. However, because of the
variety of applications and environments where analog modules are installed and
operating, it is impossible to ensure that all environmental noise will be removed
by the input filters.
Although it is not the purpose of this installation instruction to address SLC 500
system procedures, several specific steps can be taken to help reduce the effects
of environmental noise on analog signals:
• Install the SLC 500 system in a properly rated (i.e., NEMA) enclosure. Make
sure that the SLC 500 system is properly grounded.
• Use Belden cable #8761 for wiring the analog modules making sure that the
drain wire and foil shield are properly earth grounded.
• Route the Belden cable separate from any other wiring. Additional noise
immunity can be obtained by routing the cables in grounded conduit.
• Group analog and low voltage dc modules away from ac I/O or high voltage
dc modules.
SLC 500™ Analog I/O Modules
Publication 1746-IN008A-US-P
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