Configuring A Programmable Limit Switch (Pls) - Allen-Bradley Micro800 General Instructions Manual

Configuring a Programmable Limit Switch (PLS)

The high-speed counter has additional operating modes for implementing a
Programmable Limit Switch (PLS). The PLS function is used to configure the
High-Speed Counter to operate as a PLS or as a rotary cam switch. The PLS
function supports up to 255 pairs of high and low presets, and can be used when
you need more than one pair of high and low presets.
Enabling PLS in the HSC
The PLS mode only operates in tandem with the HSC of the Micro800
controller, and must be enabled in the HSC by setting the
HSCAppData.PLSEnable parameter to True.
HSC operation when PLS is enabled
The PLS function can operate with all other HSC capabilities, including the
ability to select which HSC events generate a user interrupt. When the PLS
function is enabled, and the controller is in run mode, the HSC counts incoming
pulses, and the following events occur.
•
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.
•
When the HSC counts to the new preset, the new output data is written
through the HSC mask.
•
This process continues until the last element within the PLS data block is
loaded.
•
At that point the active element within the PLS data block is reset to zero.
•
This behavior is referred to as circular operation
Rockwell Automation Publication 2080-RM001D-EN-E - February 2015
High-Speed Counter (HSC) instructions
Chapter 14
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