Calculate The Spreader Constant Value; Formula Calculation - Raven SCS660M Installation & Service Manual

Chapter 2
Measure the distance (in inches/cm) from the ground starting mark to the stopping mark. Round off fractions
4.
of an inch/cm.
Write down this number as it will be used as the Speed Cal value when programming the console.
5.
Note:
Large tires and very low speed applications may require additional magnets to ensure accurate
speed readings. Any even number of magnets may be used as long as they alternate in color and
are equally spaced. After calculating the Speed Cal value, the number must be adjusted according
to the actual number of magnets used.
For Example:
Normal Number of Magnets
Actual Number of Magnets

Calculate the Spreader Constant Value

The Spreader Constant value can be calculated in one of two ways: by performing a mathematical calculation,
or by performing a "catch test" by applying and measuring the product used.
Note:
The Spreader Constant value must be recalculated every time the gate opening dimensions are
changed.

Formula Calculation

First, use a tape measure to measure the following dimensions on the machine:
•
Gate height (GH) in inches [cm]
•
Gate width (GW) in inches [cm]
•
Distance of travel (D) in inches [cm] of the belt per one revolution of the sensor
Second, determine the number of pulses emitted by the encoder per one revolution of the sensor.
Enter a METER CAL value of 10.
1.
Enter a TOTAL VOL value of 0.
2.
Turn the sensor exactly one revolution. The value in TOTAL VOLUME is the number of encoder pulses per
3.
sensor revolution.
Third, determine the cubic feet [cm] of discharge per one revolution of the sensor by multiplying the distance of
the belt travel per one sensor revolution by the gate height by the gate width, then dividing it by 1728 (not
necessary for determining cubic cm).
For Example:
Distance of Belt Travel per 1 Sensor Revolution (D)
Gate Height (GH)
Gate Width (GW)
Number of Encoder Pulses per 1 Sensor Revolution (P)
6 SCS 660 & 660M Serial Interface for Granular Applications Installation & Service Manual
x Calculated Speed Cal
4 x
6
= Adjusted Speed Cal
1200 = 800
= 13 inches [33 cm]
= 7 inches [18 cm]
= 15 inches [38 cm]
= 180