Rockwell Automation 1756-HSC ControlLogix High Speed Counter Module - Manual (Page 11)

11 Rockwell Automation Publication 1756-UM007C-EN-P - November 2011
Chapter
1
1756-HSC Module Features
Introduction
The High-speed Counter Module (catalog number 1756-HSC) performs
high-speed counting for industrial applications. This chapter provides an
overview of the design and features of the 1756-HSC/B module.
For other module series, firmware, and/or software information, see
Appendix C .
What is a High-speed
Counter Module?
The 1756-HSC module counts pulses by using a Counter or Frequency
operational mode. The counts are presented as either ‘accumulated count’ or
‘frequency’ depending on the mode that is configured for the module.
You can choose from either one of three Counter modes or one of three
Frequency modes when configuring the module. The operational mode
selected determines how the pulse count is stored and the behavior of the
outputs.
You can manipulate the storage of the count values (detailed in Chapter 2 ). The
1756-HSC module evaluates these count values against user configured presets
and/or values, thus the response time for activating outputs is performed at a
faster rate than evaluating in the controller.
Configuration tags, which are automatically installed with the 1756-HSC
module during the initial download in RSLogix 5000 programming software,
determine whether the module interprets pulses as:
• accumulated count - values can be 1…16 million.
• frequency - positive or negative depending on the direction of the
rotation.
Pulse count values can be calculated by using different types of Counter and
Frequency modes. The simple counter uses only input A to count pulses. An
encoder uses both input A and input B to count pulses. The relationship
between the two channels is how the encoder determines if the count is
positive (clockwise) or negative (counterclockwise).
Topic Page
What is a High-speed Counter Module? 11
Encoder and Sensor Compatibility 13
1756-HSC/B Module Features 13