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Publication 1766-RM001A-EN-P - October 2008
Chapter
5
Using the High-Speed Counter and
Programmable Limit Switch
High-Speed Counter
Overview
All MicroLogix 1400, except the 1766-L32AWA and 1766_L32AWAA, have
six 100kHz high-speed counters. There are three main high-speed
counters (counter 0, 1, 2) and three sub high speed counters (counter 3, 4,
5). Each main high-speed counter has four dedicated inputs and each sub
high-speed counter has two dedicated inputs. HSC0 utilizes inputs 0…3,
HSC1 utilizes inputs 4…7, HSC2 utilizes inputs 8…11, HSC3 utilizes inputs
2 and 3, HSC4 utilizes inputs 6 and 7 and HSC5 utilizes inputs 10 and 11.
In some cases, a sub counter will be disabled by master counter mode.
See the section HSC Mode (MOD) on page 116.
This chapter describes how to use the HSC function and also contains
sections on the HSL and RAC instructions, as follows:
•
High-Speed Counter (HSC) Function File on page 100.
•
HSL - High-Speed Counter Load on page 130.
•
RAC - Reset Accumulated Value on page 131.
Programmable Limit
Switch Overview
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. See page 132 for more information.
TIP
HSC0 is used in this document to define how any HSC works.
IMPORTANT
The HSC function can only be used with the controller’s embedded I/O. It
cannot be used with expansion I/O modules.
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