Calculate scale factor
May 2019
LM_OGP2Adv_BA_99_0045
Page 41
10.
CALCULATE SCALE FACTOR
A scale factor is a number used to adjust meter accuracy. The scale factor is set at the factory using motor oil with a viscosity of
10W.
The primary use for scale factor recalibration is to batch fluids with different viscosities. If the fluid has a lower viscosity, more
fluid can slip past the meter gears without being detected. Changing the scale factor adjusts the meter to compensate for the
loss.
The meter multiplies each pulse by the scale factor number to correct the accuracy when it converts to the specified units. The
reading is then always correct.
For an approximate scale factor for fluids of different viscosities, consult the
NOTE:
The meter’s original scale factor was written on the trigger when it was calibrated at the factory. It may have been
revised after field installation. Use the scale factor showing on the display, not on the trigger.
CHANGING THE SCALE FACTOR WILL CHANGE THE ACCURACY OF THE METER, POTENTIALLY
CAUSING IT TO OVERFILL OR UNDER FILL. THIS HAS THE POTENTIAL TO CAUSE A MECHANICAL
BREAKDOWN.
To view the current scale factor:
Press and hold the
TOTAL
button and the
AUTO
button at the same time.
10.1
Absolute scale factor
For absolute scale factor, perform this test:
1.
Run a measured amount of fluid through the meter.
2.
If the meter delivers 4.20 quarts and the display shows only 4.00 quarts, then the scale factor needs to be adjusted.
3.
Divide what the meter delivered (4.20) by what the display shows (4.00). You get an error factor of (1.05).
4.
The existing scale factor is 1.0123, as shown under “To view the current scale factor”, above.
5.
To calculate a new factor:
1.0123 (existing scale factor) x 1.05 (error factor) = 1.0629 (new scale factor).
6.
Enter that number as described in "Change scale factor".
NOTE:
Use the scale factor showing on the display, not on the trigger.
