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Flow-X─ Function Reference
Flow-X IO Functions - fxTimePeriodInput
fxTimePeriodInput
This function measures the time period between two pulses with a high resolution (100 nanoseconds)
and is typically used for densitometer inputs. The measurement is performed continuously in the
background and the function returns the average value since the previous calculation cycle.
The measured time period value can be linked to a subsequent densitometer-specific (Solartron,
Sarasota, UGC) function that calculates the density at the densitometer conditions.
Abnormal measurements are filtered out and alarmed for.
Function inputs
Remark
EU
SW tag
Range
Default
Name
Optional tag name, tag
description and tag group
Channel
Channel number for the signal
-
CHAN
1..16
0
Time period differential
limit
Maximum allowable difference
in microseconds.
When the time period between
two consecutive pulses differs
more than this limit from the
previous time period, the
reading is considered to be
abnormal.
Following an abnormal reading
there must be 3 consecutive
readings within the limit before
the time period value is
considered normal again.
When no 3 consecutive readings
within the limit are available in
the last 5 readings then the
input signal is considered to be
invalid.
Resolution of the limit value is
100 nanoseconds.
μs
Minimum stable time
Minimum time for high- and
low-times of a pulse to be
considered valid.
μs
0..10000
30
Function
outputs
Remark
EU
SW tag
Alarm
Fallback
Status
0: Normal
1: Input argument out of range
Outputs will be set to fallback values
2: No valid measurement
Outputs will be set to fallback values
STS
INPERR
(*)
Time period
Average (arithmetic mean) in
microseconds of the last calculation
cycle
μs
TIME
0
Frequency
Average (arithmetic mean) of the last
calculation cycle
Hz
FREQ
0
Curcount
Current counter value
CURCNT
0
Curtime
Current time value
sec
CURTIME
0
Oldcount
Previous counter value
PRVCNT
0
Oldtime
Previous time value
sec
PRVTIME
0
(*) Note that no alarm is generated for this status output value. This is to avoid an unnecessary alarm in
case the input is not used
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