Spectrum Controls 1746sc-CTR4 - Manual (Page 30)

30
SLC 500 ™ 50 KHz Counter / Flowmeter Module
Reset Flags: (Configuration Bit 2)
The reset flags command is performed when this bit is set. Reset flags
affects the counter zero, counter limit and counter maximum flags
(Status word bits 8, 6, and 5 respectively.) These particular flags remain
high, regardless of the counter behavior, until a reset is performed. This
allows adequate time to read the flags after an event has occured.
If user Counter Limit is set to 0 (0 indicates undefined), these flags will
remain high until reset:
Count is equal to zero or counter decremented down through zero flag
(Status word bit 8).
Count up or down through the maximum count flag
(Status word bit 5).
If a Counter Limit is never set (Status word bit 6) the flags will not
annunciate.
If user Counter Limit is set to a non-zero value ( User defined limit), these
flags are will remain high until reset:
Count is equal to zero or counter decremented down through zero flag
(Status word bit 8).
Count up or down through the limit flag (Status word bit 6).
And these flags do not remain high:
Maximum count flag (Status word bit 5) is set if count value is
exactly equal to 32,767 (16 bit) or 8,388,607 (24 bit). Otherwise it is
clear.
Rate Mode: (Configuration Bit 3)
Refer to Appendix A for Floating Point Rate Mode
Rate - Average:
When the rate mode bit is set to a “1” the rate detection circuit is in
“Rate Average” mode. The rate average mode counts the number of
input transitions over a 1 second interval and calculates the input rate
averaged over the 1 second interval. The rate average mode is slow, in
that it reports updated rates at once per second. However this mode is
accurate to ± 1 count over the full range of measurement.
Figure 4.4 - One Second Rate Average
One Second Average of Periods