Rockwell Automation 1756-HSC ControlLogix High Speed Counter Module - Manual (Page 68)

Rockwell Automation Publication 1756-UM007C-EN-P - November 2011
68 Configure the 1756-HSC Module
3. Click OK.
Filter Selections
High-speed inputs can be sensitive to electromagnetic noise. You can manually
set Channel 0 inputs and/or Channel 1 inputs to filter out noise or debounce.
Debounce is created when a mechanical device changes state (On/Off).
All 1756-HSC module inputs have the following characteristics:
• With the filter disabled (assuming a 50% duty cycle):
– module reads at 1 MHz in Counter mode.
– module reads at 250 kHz in Encoder x1 or Encoder x4 mode.
– module reads at 500 kHz in Frequency mode.
• With the filter enabled (assuming a 50% duty cycle):
– module counts all pulses at a frequency below 70 Hz.
– module does not count any pulses at a frequency above 150 Hz.
– frequencies between 71…148 Hz the operation is unpredictable and
varies with duty cycles.
Set Up Output Configuration
The Output Configuration tab (on the Module Properties dialog box) is
available for either the HSC Data or HSC Data-extended Comm Format with
the 1756-HSC/B module. The tab lets you set up and maintain the four
on-board outputs, which compare user-defined values to the Present Value tag
to turn outputs On or Off.
Follow these steps to set up the output operation.
1. On the Modules Properties dialog box, click the Output Configuration
tab.
Use Filter A
Use Filter B
Use Filter Z
Select a filter for either Channel 0
and/or Channel 1.
See Filter Selections for how the filters
affect the signal rate.
Invert Z Value Box becomes active when a Storage
mode is selected other than ‘No Store
Mode.’ When active, Input Z reverses
reading the rising or falling edge of the
pulse depending on previous usage. If
the pulse was read on the rising edge,
the module inverts the signal and now
reads the falling edge of the pulse.
Field Description