Rockwell Automation 1771-VHSC , D17716.5.74 Very High S User Manual

Page 16

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1–8 Overview of the Very High Speed Counter Module

In mode 1, store/continue (1.4), the leading edge of a pulse input on
the gate/reset terminal will cause the current value in the counter to
be read and stored. The counter will continue counting. The stored
count will be available in the block transfer read file. The stored
count information will remain in the block transfer read file until it is
overwritten by new data.

Figure 1.4

Store/Continue

Read, Store Count

and continue counting.

10680ĆI

In mode 2, store/wait/resume (1.5), the gate/reset terminal provides
the capability to inhibit counting when the gate/reset input is high.
Counting resumes when the input goes low. Mode 2 does not reset
the counter, although it does store the count value.

Figure 1.5

Store/Wait/Resume

Store Count

Stop counting

Resume counting

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In mode 3, store-reset/wait/start (1.6), the rising edge of the pulse
on the gate/reset terminal causes the counter to stop counting, store
the current count value in the block transfer read file and reset the
count to zero. The counter does not count while the input pulse on
the gate/reset terminal remains high. Counting resumes from zero on
the falling edge of the pulse at the gate/reset terminal.

Figure 1.6

StoreĆReset/Wait/Start

Stop count, store

and reset to zero

Counter has stopped counting

Start counting

from zero

10682ĆI

In mode 4, store-reset/start (1.7), on the rising edge of a pulse
input at the gate/reset terminal will cause the counter to store the
accumulated count value and will reset the counter to zero. The
counter continues counting, and the stored count is available in the
block transfer read file.

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