AW Gear Meters RT-15 - Manual (Page 20)

RT‐15 Flow Monitor
Operation and Programming Manual
19
KFR = Time Base Constant/K‐FACTOR
where:
 100 is the time base constant for engineering units per second
 6000 is the time base constant for engineering units per minute
 360000 is the time base constant for engineering units per hour
 8640000 is the time base constant for engineering units per day
 K‐FACTOR is the average number of pulses per desired engineering unit that the
transducer produces
Method
1. Determine the number of decimal places desired for rate display.
2. Round off the result of the formula to the desired accuracy.
3. Enter the KFR using only that number of decimal places.
Using too few decimal places can cause relatively large display errors, up to several percent of actual
reading. Using too many decimal places can result in displays with a level of precision exceeding the
accuracy of the meter. Use no more than four digits regardless of decimal point position! The largest
acceptable value for KFR is 65535 with the decimal in any location.
For example:
A flow meter has a K‐factor of 2053.57 imp/Gal and the display should read in Gal/Min. with accuracy to
three decimal places.
KFR = 6000/2053.57 = 2.921741 for GPM
Round off 2.921741 to three decimal places and enter 2.922 for KFR.
When entering or editing the KFR value, the leftmost digit will blink (cursor). Use the SEL button (or
magnetic switch) to select the digit to edit; the cursor moves to the right and wraps around. You can
relocate the decimal point when it is selected (blinking). Use the UP or DN button or (magnetic switch)
to increase or decrease the variable value, or to move the decimal point. Use DN to move the decimal
point to the right, UP to move it to the left. When the desired value displays, use the ENT button (or
magnetic switch) to store the programmed value and advance to the next variable.
Gate time (GATE A B)
This variable sets the sample time on the incoming frequency for the RATE A GT (Gate Time) displays.
Programmed in tenths of a second with an allowable range from .01 to 600 seconds, this variable affects
the update of the display and analog output, and is useful in stabilizing the display and output when
dealing with slight variations in flow. Do not set GATE TIME to zero as it will disable rate display.