Linearity Test; Off-Center Load Test; Linearity Test Masses - OHAUS Valor 2000 Service Manual

4.4.3 Linearity Test

This test is used to determine the linearity of the unit throughout its operating range.
The masses used to perform this test can be utility masses
The scale must pass the Precision and Repeatability Tests, and be calibrated before
the Linearity Test may be performed.
All masses are nominal values. Use the same reference mass throughout the procedure.
1. Place the test mass on the Scale, record the weight and remove.
2. Place Load 1 on the Scale and press ON/ >O/T<.
3. Place the test mass on the Scale, record the weight and remove.
4. Place Load 2 on the Scale and press ON/ >O/T<.
5. Place the test mass on the Scale, record the weight and remove.
6. Place Load 3 on the Scale and press ON/ >O/T<.
7. Place the test mass on the Scale and record the weight.
8. The difference in the weights of the test mass should be within ±1 d. If not, calibrate
(see Appendix A.1) and repeat the test.
9. If the Scale remains out of tolerance, the Load Cell may need to be replaced.

4.4.4 Off-Center Load Test

The Off-Center Load Test is used to determine whether displayed weight values are affected by
moving the sample to different areas of the Pan.
1. Place half of the scale's capacity in the center of the Pan.
2. Note the reading.
3. Move the mass halfway (between the center and the edge) to the front of the Pan.
Note any differences in the displayed weight reading.
4. Repeat the test for the back, left, and right position of the Pan.
5. Maximum allowable change in displayed weight readings for each of the four
positions can be found in Tables 1-2 (Specifications, page 1-3). If this maximum is
exceeded, follow procedures in Section 4.4.5, Adjusting Off Center Load.
Valor™ 2000 Series Service Manual
TABLE 4-3. LINEARITY TEST MASSES
3000 x .5g
Capacity (g)
Reference Wt. 750
Load 1 750
Load 2 1500
Load 3 2250
NOTE:
4-5
NOTE:
6000 x 1g 15000 x 2g
1500 3000
1500 3000
3000 9000
4500 12000
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CHAPTER 4 TESTING