Badger Meter K-Factor Scaler - Manual (Page 12)

Setting the Output Level Normally High or Normally Low
Most end devices will be unaffected by this setting but the K Factor Scaler has the ability to invert the output pulse level
This option is set by selecting the desired pulse output radio button in the Program Values column of the software The pulse
output option will be programmed into the board when Program is pressed, but note that all values must be entered before
programming is allowed by the software
When the pulse output option High is selected, the output level is normally low and the duration of the selected pulse width
is high When the pulse output option Low is selected, the output level is normally high and the duration of the selected pulse
width is low
Setting the Output to Use the Internal or External Pullup Resistor
Either the internal pullup resistor or an external resistor must be used for the K Factor Scaler to provide an output pulse This
option is controlled by the onboard jumper and not by the software
With the jumper installed, the internal 3 6 kΩ pullup resistor is connected to the input voltage of the board With the jumper
removed, the internal pullup resistor is disconnected and an external pullup resistor and supply voltage are required
K FACTORS EXPLAINED
The K factor (with regards to flow) is the number of pulses that must be accumulated to equal a particular volume of fluid You
can think of each pulse as representing a small fraction of the totalizing unit
An example might be a K factor of 1000 (pulses per gallon) This means that if you were counting pulses, when the count total
reached 1000, you would have accumulated 1 gallon of liquid Using the same reasoning, each individual pulse represents an
accumulation of 1/1000 of a gallon This relationship is independent of the time it takes to accumulate the counts
The frequency aspect of K factors is a little more confusing because it also involves the flow rate The same K factor number,
with a time frame added, can be converted into a flow rate If you accumulated 1000 counts (one gallon) in one minute, then
your flow rate would be 1 gpm The output frequency, in Hz, is found simply by dividing the number of counts (1000) by the
number of seconds (60) to get the output frequency
1000 ÷ 60 = 16 6666 Hz If you were looking at the pulse output on a frequency counter, an output frequency of 16 666
Hz would be equal to one gpm If the frequency counter registered 33 333 Hz (2 × 16 666 Hz), then the flow rate would be
two gpm
Finally, if the flow rate is two gpm, then the accumulation of 1000 counts would take place in 30 seconds because the flow
rate, and hence the speed that the 1000 counts is accumulated, is twice as great
Calculating K factors
Many styles of flow meters are capable of measuring flow in a wide range of pipe sizes Because the pipe size and volumetric
units the meter will be used on vary, it may not possible to provide a discrete K factor In the event that a discrete K factor is
not supplied then the velocity range of the meter is usually provided along with a maximum frequency output
The most basic K factor calculation requires that an accurate flow rate and the output frequency associated with that flow rate
be known
Example 1
Known values are:
Frequency = 700 Hz
Flow Rate = 48 gpm
700 Hz × 60 sec = 42,000 pulses per min
42,000 pulses per min
K factor
48 gpm
875 pulses per gallon = =
Signal Conditioner, B220-885 K Factor Scaler and B220-900 Programming Software Kit
Page 12 November 2013