218 Rockwell Automation Publication 2080-UM002N-EN-E - November 2022
Chapter 10 Use the High-Speed Counter and Programmable Limit Switch
Programmable Limit Switch
(PLS) Function
The Programmable Limit Switch function allows you to configure the High-Speed Counter to
operate as a PLS (programmable limit switch) or rotary cam switch.
When PLS operation is enabled (HSCAPP.PLSEnable = True), the HSC (High-Speed Counter) uses
PLS data for limit/cam positions. Each limit/cam position has corresponding data parameters
that are used to set or clear physical outputs on the controller’s base unit. The PLS data block
is illustrated in Figure 20 on page 218
.
PLS Data Structure
The Programmable Limit Switch function is an additional set of operating modes for the High-
Speed Counter. When operating in these modes, the preset and output data values are updated
using user supplied data each time one of the presets is reached. These modes are
programmed by providing a PLS data block that contains the data sets to be used.
PLS data structure is a flexible array, with each element defined as follows,
The total number of elements for one PLS data cannot be larger than 255.
When PLS is not enabled, PLS data are still required to be defined, but can be not initialized.
Figure 20 - PLS Data Block
PLS Operation
When the PLS function is enabled, and the controller is in the run mode, the HSC counts
incoming pulses. When the count reaches the first preset (HSCHP or HSCLP) defined in the PLS
data, the output source data (HSCHPOutput or HSCLPOutput) is written through the HSC mask
(HSCAPP.OutputMask).
At that point, the next presets (HSCHP and HSCLP) defined in the PLS data become active.
IMPORTANT The PLS Function only operates in tandem with the HSC of a Micro830
controller. To use the PLS function, an HSC must first be configured.
Element Order Data Type Element Description
Word 0…1 DINT High preset setting
Word 2…3 DINT Low preset setting
Word 4…5 UDINT High preset Output data
Word 6…7 UDINT Low preset Output data
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