11
RATE DISPLAY EXCEEDED
If the rate of the input signal causes a display that exceeds the capacity of the
Rate display (5 digits, 99999), then the display will indicate an overflow
condition by showing “
! *#*#
”. During this overflow condition, the Minimum
and Maximum rate values will stay at their values even during resets.
RATE SCALING
To scale the Rate, enter a Scaling Display value with a corresponding Scaling
Input value. (The Display and Input values can be entered by Key-in or Applied
Methods.) These values are internally plotted to a Display value of 0 and Input
value of 0 Hz. A linear relationship is formed between these points to yield a
rate display value that corresponds to the incoming input signal rate. The PAXR
is capable of showing a rate display value for any linear process.
KEY-IN SCALING METHOD CALCULATION
If a display value versus input signal (in pulses per second) is known, then
those values can be entered into Scaling Display (
!%&+$,
) and Scaling Input
(
!%&'(,
). No further calculations are needed.
If only the number of pulses per ‘single’ unit (i.e. # of pulses per foot) is
known, then it can be entered as the Scaling Input value and the Scaling Display
value will be entered as the following:
NOTES
:
1. If # of pulse per unit is less than 10, then multiply both Input and Display
values by 10.
2. If # of pulse per unit is less than 1, then multiply both Input and Display
values by 100.
3. If the Display value is raised or lowered, then Input value must be raised
or lowered by the same proportion (i.e. Display value for per hour is
entered by a third less (1200) then Input value is a third less of # of pulses
per unit). The same is true if the Input value is raised or lowered, then
Display value must be raised or lowered by the same proportion.
4. Both values must be greater than 0.0.
EXAMPLE:
1. With 15.1 pulses per foot, show feet per minute in tenths. Scaling Display
= 60.0 Scaling Input = 15.1.
2. With 0.25 pulses per gallon, show whole gallons per hour. (To have greater
accuracy, multiply both Input and Display values by 10.) Scaling Display
= 36000 Scaling Input = 2.5
RATE PER
DISPLAY (
!%&+$,
)
INPUT (
!%&'(,
)
Second
1
# of pulses per unit
Minute
60
# of pulses per unit
Hour
3600
# of pulses per unit
INPUT FREQUENCY CALCULATION
The meter determines the input frequency by summing the
number of falling edges received during a sample period of
time. The sample period begins on the first falling edge. At this
falling edge, the meter starts accumulating time towards Low
Update and High Update values. Also, the meter starts
accumulating the number of falling edges. When the time
reaches the Low Update Time value, the meter looks for one
more falling edge to end the sample period. If a falling edge
occurs (before the High Update Time value is reached), the Rate
display will update to the new value and the next sample period
will start on the same edge. If the High Update Time value is
reached (without receiving a falling edge after reaching Low
Update Time), then the sample period will end but the Rate
display will be forced to zero. The High Update Time value
must be greater than the Low Update Time value. Both values
must be greater than 0.0. The input frequency calculated during
the sample period, is then shown as a Rate value determined by
either scaling method.
