Rockwell Automation 1794-VHSC 1794 FLEX I/O Very High Speed Counter Module User Manual - Manual (Page 9)

Rockwell Automation Publication 1794-UM010D-EN-E - July 2013 1
Chapter
1
Overview of the Very High Speed
Counter Module
Overview This chapter gives you information on features of the modules, how the module
communicates with controllers and how the module operates.
Module Description The 1794-VHSC module performs high speed counting for industrial
applications. The module is an intelligent I/O module that interfaces signals with
any Allen-Bradley programmable controller that has Ethernet capability.
The 1794-VHSC module, once configured for its intended purpose, can
continue to operate without FlexBus power.
After scanning the inputs and updating the outputs, the input data is converted to
a specified data type in a digital format to be transferred to the processor’s data
table on request. Command and configuration data is sent from the
programmable controller data tables to the module via Ethernet.
Module Features
The 1794-VHSC module counts pulses from encoders (such as Allen-Bradley
Bulletin 845), pulse generators or mechanical limit switches, or proximity
switches, and returns either a count or frequency in binary format.
Topic Page
Module Description 1
Encoder or Counter Mode 2
Period/Rate Mode 8
Continuous/Rate Mode 10
Rate Measurement Mode 11
Pulse Width Modulation 12
Outputs 13
What the Module Does 14
IMPORTANT Customer power is required for the module, inputs and outputs.