Appendix c, C – schematics, What this appendix contains – Rockwell Automation 1794-IJ2XT FLEX I/O Frequency Input Modules User Manual User Manual
Page 71: Gate inputs, Schematics, Appendix
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Publication 1794-6.5.11 - September 2011
Appendix
C
Schematics
What This Appendix
Contains
Use this appendix to understand the internal logic of the FLEX I/O
Frequency Input module.
Follow the wiring practices described in Industrial Automation Wiring and
Grounding Guidelines for Noise Immunity, publication
1770-4.1
, when wiring
your I/O devices. This includes:
• routing conductors
• grounding practices
• use of shielded cables
• input circuits
The frequency input module input logic consists of:
• frequency input circuits
• gate input circuits
• Frequency Inputs
The frequency input circuit uses a comparator to determine when the input
voltage threshold is exceeded. When exceeded, it provides logic pulses internal
to the 1794 Frequency Input module. The circuit is designed to interface with
both active or passive sensor inputs by accepting any pulse output device (such
as vortex flowmeter, magnetic pickup or digital pickup).
Gate Inputs
Gate inputs are similar to frequency inputs and are used for determining
direction. There is one gate associated with each frequency input circuit (G0
corresponds to F0). The circuit is designed to interface with both active or
passive sensor inputs by accepting any pulse output device (such as magnetic
pickup or digital pickup).