Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 27)

Publication 1746-UM002B-EN-P - August 2004
Module Operation 2-7
Store/Hold/Resume
The count value, captured when the module detects a positive
transition on the Z input, is made available to the backplane. A stored
status bit is set in the input image table to signal the processor that a
new value is available. This bit is active until the capture value is read
by the processor. Therefore, it is on for a maximum of 10 ms in Class
1, and a maximum of one scan or 10 ms, whichever is shorter, in Class
4. The count value is held as long as the Z input is active. Because the
count value is not changing, the rate value is equal to zero while the
counter is held.
Store/Preset/Hold/Resume
The counter is set to its programmed preset value when the module
detects a positive transition on the Z input of the counter. The capture
value is made available to the backplane. A stored status bit is set in
the input image table to signal the processor that a new value is
available. This bit is active until the capture value is read by the
processor. Therefore, it is on for a maximum of 10 ms in Class 1, and
a maximum of one scan or 10 ms, whichever is shorter, in Class 4. The
preset counter value is held as long as the Z input remains active.
Because the count value is not changing, the rate value equals zero
while the preset value is held.
Store/Preset/Start
The counter is set to its programmed preset value when the module
detects a positive transition on the Z input of the counter. The capture
value is made available to the backplane. A stored status bit is set in
the input image table to signal the processor that a new value is
available.This bit is active until the capture value is read by the
processor. Therefore, it is on for a maximum of 10 ms in Class 1, and
a maximum of one scan or 10 ms, whichever is shorter, in Class 4.
counter has stopped counting
stop count
store count
resume
counting
start
counting
from preset counter has
stopped counting
stop count,
store count,
store count,
preset, start
counting