Allen-Bradley 2080-DNET20, Руководство пользователя

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32 Rockwell Automation Publication 2080-UM004C-EN-E - March 2015
Appendix 4 High Speed Counter – 2080-MOT-HSC
flag will be set to indicate that a rollunder has occurred. It is reset using the
ResetCountUnderflow_n bit.
1: linear counter.
When the counter is a linear counter and the present count
value is equal to MaxCountValue_n the next input count in the up direction will
activate the CountOverflow_n bit and also the PresentCount_n will remain at
the MaxCountValue_n. CountOverflow_n is reset using the
ResetCountOverflow_n bit.
Conversely, when the PresentCount_n is equal to MinCountValue_n the next
input count in the down direction will activate the CountUnderflow_n bit and
the PresentCount_n will remain at MinCountValue_n. CountUnderflow_n is
reset using the ResetCountUnderflow_n bit.
IMPORTANT
The counts in overflow and underflow will not be accumulated at all.
That is, even if 1000 pulses are applied while in overflow, the first pulse
with the opposite direction (down in this case) will cause the counter to
be decremented by 1. (The CountOverflow_n bit is only reset using the
ResetCountUnderflow_n bit.)
Rollover
MinCountValue MaxCountValue
Count Up
Count Down