OHAUS Navigator NV212, Service Manual

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CHAPTER 4 TESTING
Navigator Series Service Manual 31 Ohaus Corporation www.ohaus.com
9. The difference in the weights of the test mass should be within the tolerance in Table 4-2. If
the differences are out of tolerance, calibrate (see Appendix A.1) and repeat the test.
10. If the Scale remains out of tolerance, the Load Cell may need to be replaced.
4.5.4 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.
11. Place half of the
scale’s capacity in the center of the Pan.
7. Note the reading.
8. Move the mass halfway (between the center and the edge) to the front of the Pan. Note any
differences in the displayed weight reading.
9. Repeat the test for the back, left, and right position of the Pan.
10. Maximum allowable change in displayed weight readings for each of the four positions can
be found in Specifications Tables (Chapter 1). If this maximum is exceeded, follow
procedures in Section 4.5.5, Adjusting Off Center Load.
4.5.5 Adjusting Off Center Load
If the Off Center Load (OCL) is excessive, perform adjustment as follows:
Figure 4-4. Navigator Load Cell and Weighing Pan
1. Place the test weight in the center of the Weighing Pan.
2. Tare the balance.
3. Move the weight to point A and record the reading.
Top view of Load Cell
Weighing Pan’s
center, with points
A
– D indicated
Side view of Load Cell
1
2 3
4