Ohaus Corporation www.ohaus.com
52
Ranger 7000
®
Series Service Manual
Repeatability Test – Approved models
This test is a variation of the test above. Rather than determining acceptance based on the
standard deviation of the errors, MPE is used. The other variation is that 2 series of weighings are
used, one near 50% of max and the other near 100% of maximum capacity.
1. See Table 1-1 to determine the two weight values that must be used.
2. Record 10 reading using each weight value. Zero the scale between each reading if
necessary.
3. The difference between the results of the 10 readings must be less than the absolute value
of the Maximum Permissible Error (MPE) for the load. The MPE for each load in grams is
given in Table 1-1.
4.3.3 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.
This is a reference test for approved scale s as there is no linearity specification. The approved
models should be able to pass this test so it is still valid to determine scale performance.
NOTE:
The scale must pass the Precision and Repeatability Tests, and be calibrated before the
Linearity Test is performed.
TABLE 4-3
LINEARITY TEST - REFERENCE AND LOAD MASSES
Model
Load 1
Load 2
Load 3
R71MHD3
0kg
1.5kg
3kg
R71MHD6
0kg
3kg
6kg
R71MHD15
0kg
10kg
15kg
R71MHD35
0kg
20kg
35kg
R71MD3
0kg
1.5kg
3kg
R71MD6
0kg
3kg
6kg
R71MD15
0kg
10kg
15kg
R71MD35
0kg
20kg
35kg
NOTE: All masses are nominal values. Be certain to use the same reference mass throughout the
procedure.
1. Place the Reference Mass on the scale, record the weight and remove.
2. Place Load 1 on the scale and press TARE.
3. Place the test mass on the scale, record the weight and remove.
4. Place Load 2 on the scale and press TARE.
5. Place the test mass on the scale, record the weight and remove.
6. Place Load 3 on the scale and press TARE.
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 the tolerance in Table 4-2. If
the differences are out of tolerance, verify the test conditions and repeat the test.
9. If the scale remains out of tolerance, the Load Cell may need to be replaced.
Summary of Contents for Ranger 7000 R71MHD3
Page 1: ...Ranger 7000 Scale Service Manual...
Page 2: ......
Page 5: ...TABLE OF CONTENTS Ohaus Corporation www ohaus com iii Ranger 7000 Service Manual...
Page 11: ...Ranger 7000 Series Service Manual 9 Ohaus Corporation www ohaus com...
Page 30: ...Ohaus Corporation www ohaus com 28 Ranger 7000 Series Service Manual...
Page 58: ...Ohaus Corporation www ohaus com 56 Ranger 7000 Series Service Manual 5 1TERMINAL SPARE PARTS...
Page 77: ...Ohaus Corporation www ohaus com 75 Ranger 7000 Series Service Manual...
