OHAUS Ranger 7000 R71MHD15, Service Manual

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Ranger 7000
®
Series Service Manual 53 Ohaus Corporation www.ohaus.com
4.3.4 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. OCL test may also be referred to as a Shift Test
(NTEP) or an Eccentricity Test (OIML).
The test weight used in this test 1/3 the capacity of the scale. See table for the test weight values.
TABLE 4-4 OFF CENTER LOAD MASS VALUES
Model OCL Mass Value Notes
R71MHD3 0 kg, 1.5 kg, 3 kg
1. The class of test weight to be use during OCL is not critical.
R71MHD6 0 kg, 3 kg, 6 kg
R71MHD15 0 kg, 10 kg, 15 kg
2. Use large weights where possible. Smaller weights can be
R71MHD35 0 kg, 20 kg, 35 kg
stacked on the larger but a stability problem may occur if many
R71MD3 0 kg, 1.5 kg, 3 kg
smaller weights are used. If weights cannot be stacked they
R71MD6 0 kg, 3 kg, 6 kg
must be placed uniformly over the segment.
R71MD15 0 kg, 10 kg, 15 kg
R71MD35 0 kg, 20 kg, 35 kg
The test positions (A-D) must be centrally located in each segment.
A
B
D
C
A
B
D
C
Round Pan Rectangular Pan
Procedure:
1. Set AZT (Auto Zero Tracking) to off. This setting is located in Menu - Scale Setup - AZT menu.
2. Place the test weight in the center of the Weighing Pan.
3. Tare the scale.
4. Move the weight to location A and record the reading (when stability indicator comes on).
5. Move the weight to location B and record the reading.
6. Move the weight to location C and record the reading.
7. Move the weight to location D and record the reading.
8. 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 verify the test
conditions and retest the scale. If there is no improvement the load-cell must be replaced.