Rice Lake Scout Pro Series Portable, Ohaus - Service Manual - Manual (Page 21)

4-3
CHAPTER 4 TESTING
4.2.2 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 (6).
Test
1. Place 1/2 of the balance capacity in the center of the Pan (1).
2. Note the reading.
3. Move the mass halfway (between the center and the edge) to the front of the Pan (1). Note
any differences in the displayed weight reading.
4. Repeat this test for the back, left, and right positions of the Pan.
5. Maximum allowable change in displayed weight readings is + 2 count for each of the four
positions. If this reading is exceeded, it usually indicates a defective Transducer (8).
4.2.3 Linearity Test
This test is used to determine the linearity of the unit throughout its operating range. The masses used
to perform this test must be adjusted to ASTM Class 4 Tolerance, or better.
NOTE:
The balance must pass the Off-Center Load Test and Re-
peatability Test before the Linearity Test may be performed.
Test
Loads do not have to be test weights. They can be anything that totals the load value. The test mass
can be anything that weighs near the test mass value
TABLE 4-2. TEST MASSES
Capacity Test mass Load 1 Load 2 Load 3 Load 4
200g 1g 50g 100g 150g 190g
400g x 0.01 1g 100g 200g 300g 390g
400g x 0.1 5g 100g 200g 300g 400g
600g 5g 150g 300g 450g 600g
2000g 5g 500g 1000g 1500g 2000g
4000g 5g 1000g 2000g 3000g 4000g
6000g 10g 1500g 3000g 4500g 6000g
1. Place the test mass on the balance, record the weight and then remove.
2. Place Load 1 on the balance and press the ON/ZERO/Off button.
3. Place the test mass on the balance, record the weight and then remove.
4. Place Load 2 on the balance and press the ON/ZERO/Off button.