Rockwell Automation Publication 2080-UM004C-EN-E - March 2015 33
High Speed Counter – 2080-MOT-HSC Appendix 4
Enabling and Disabling a Counter using the HSC_EN bit
Disabling the counter does not inhibit any HSC_ACC_Bn loading functions
(preset or direct write) or any Z function.
The module continuously calculates rates for each of the counters regardless of
input operational mode.
Timer
For the first two counters, a timer is used to measure the time between two
successive pulses. This value is reported to the backplane as
HSC_PULSE_WIDTH_Bn.
Understanding Rates
There are different applications which require rate information but there is no
one perfect method for all. Generally, the user must weigh rate accuracy with the
need for new information quickly.
Broadly, there are two different ways to calculate rates and optimize accuracy and
speed of the rate of calculation:
• Per Pulse
1/HSC_PULSE_WIDTH_B (supported through 2080-MOT-HSC
plug-in)
HSC_PULSE_WIDTH_Bn is reported to the user in the input array
• Cyclic
Number of Pulses/User Defined Time Interval (supported through
Connected Components Workbench)
PresentRate_n is reported to the user in the input array.
MinCountValue
MaxCountValue
Underflow
Overflow
Count Down
Count Up
0
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