OHAUS Valor 1000W Service Manual

CHAPTER 4 TESTINGValor™ 1000W Series Service Manual 4-5 Ohaus Corporation www.ohaus.com4.6.3 Linearity TestThis test is used to determine the linearity of the unit throughout its operating range.The masses used to perform this test can be utility massesNOTE:The scale must pass the Precision and Repeatability Tests, and be calibrated beforethe Linearity Test may be performed.TABLE 4-3. LINEARITY TEST MASSESCapacity (g) 3000 x .5g 6000 x 1g 15000 x 2g 30000 x 10gReference Wt. 1000 1500 4000 8000Load 1 500 1500 3000 6000Load 2 1500 3000 9000 15000Load 3 2000 4500 11000 22000NOTE: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 ±2 d, as specified inthe Tables 1-1 and 1-2. 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 TestThe Off-Center Load Test is used to determine whether displayed weight values are affected bymoving 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 fourpositions can be found in Tables 1-1 and 1-2 (Specifications, page 1-2 and 1-3).If this maximum is exceeded, follow procedures in Section 4.4.5, Adjusting OffCenter Load.