Technical data
Chapter 2: Installation
Scale Build Determination
(9/00) 2-29
Minimum Increment Size For
Optional Analog Scale Input
Minimum increment size selection for an analog scale input is determined by calculating
microvolts per increment for the desired build. To calculate microvolts per increment:
1. Solve the following equation for µV per increment (assumes using a standard
analog load cell interface module with a 15 V excitation).
Increment Size × cell output × 15000
µV per Increment = —————————————————
Load Cell Capacity × Ratio
Increment size, scale capacity, and load cell capacity must be measured in the
same weight units, lb or kg. If the variables are listed in kg units, multiply by
2.2046 to convert to lb units. Load cell output is rated in mV/V (millivolts per volt of
excitation), marked on the load cell data tag. METTLER TOLEDO load cells are
typically 2 mV/V; others range from 1 mV/V to 4.5 mV/V. Load cell capacity is the
rated capacity marked on the load cell data tag. Ratio is the number of load cells in
the system or total lever ratio (if scale is a mechanical lever system conversion).
2. Calculate total increments by dividing calibrated capacity by increment size.
3. Use the microvolt build table that follows to determine if the µV per increment
calculated in step 1 is within the range allowed for the total number of increments
calculated in step 2. These parameters have demonstrated stable builds but smaller
minimum µV per increment and larger total number of increments are possible.
Microvolt Build Table
Maximum µV per Increment Total Number of
Increments
Minimum µV per
Increment
2 mV/V 3 mV/V
600
1,000
1,200
1,500
2,000
2,500
3,000
4,000
5,000
6,000
8,000
10,000
12,000
15,000
16,000
20,000
25,000
30,000
32,000
35,000
40,000
45,000
48,000
50,000
5.0
3.0
2.5
2.0
1.5
1.2
1.0
0.75
0.6
0.5
0.375
0.3
0.25
0.2
0.18
0.15
0.12
0.1
0.1
0.1
0.1
0.1
0.1
0.1
43.3
26.0
21.7
17.3
13.0
10.4
8.7
6.5
5.2
4.4
3.3
2.6
2.2
1.7
1.6
1.3
1.0
0.87
0.81
0.74
0.65
0.58
0.54
0.52
63.3
38.0
31.7
25.3
19.0
15.2
12.7
9.5
7.6
6.4
4.8
3.8
3.2
2.5
2.4
1.9
1.5
1.3
1.2
1.1
0.95
0.84
0.80
0.76
The JAGXTREME terminal should never be programmed for less than 0.1 µV per
increment. The JAGXTREME terminal CANNOT be calibrated for builds that exceed the
maximum µV per increment listed in the microvolt build table.