122 Rockwell Automation Publication 2080-UM002L-EN-E - November 2021
Chapter 8 Use the High-Speed Counter and Programmable Limit Switch
execution of the high-speed counter interrupt routine and the immediate
update of outputs based on a source and mask pattern you set.
The HSC functions are different than most other controller instructions. Their
operation is performed by custom circuitry that runs in parallel with the main
system processor. This is necessary because of the high-performance
requirements of these functions.
Features and Operation
The HSC is extremely versatile; you can select or configure the master HSC for
any one of ten (10) modes and the sub HSC for any one of five (5) modes of
operation. See HSC Mode (HSCAPP.HSCMode)
on page 127 for more
information.
Some of the enhanced capabilities of the High-Speed Counters are:
•100 kHz operation
• Direct control of outputs
• 32-bit signed integer data (count range of ± 2,147,483,647)
• Programmable High and Low presets, and Overflow and Underflow se
t
poi
nts
• Automatic Interrupt processing based on accumulated count
• Change parameters on-the-fly (from the user control program)
The High-Speed Counter function operates as described in the following
diagram.
Figure 10 - High-Speed Counter Operation
You must set a proper value for the variables OFSetting, HPSetting, and
UFSetting before triggering Start/Run HSC. Otherwise, the controller will be
faulted. (Setting a value for LPSetting is optional for certain counting
modes.)
To learn more about HscAppData variable input, see HSC APP Data Structure
on page 125.
+2,147,483,647 maximum
-2,147,483,648 minimum
Overflow
High Preset
0
Low Preset
Underflow
HscAppData.OFSetting
HscAppData.HPSetting
HscAppData.LPSetting
HscAppData.UFSetting
Variable
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