OHAUS Defender D30BR, Service Manual

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CHAPTER 4 TESTING
4.5 Performance Tests
Accurate performance of the Defender 3000 Bases is determined by two performance tests.
The displayed readings are compared with the tolerances listed in Table 1-1.
NOTE:
The following performance tests are used to evaluate scale operation before and
after repairs. The base must meet the requirements specified in each test as
well as the specifications listed in Table 1-2. Before proceeding with the
following tests, the indicator should be calibrated. (See Section 4.3.)
4.5.1 Off Center Load (Shift) Test
The Off Center Load (Shift) Test is made before and after a Base has had the Load Cell
replaced and adjustments have been made that affect its performance. The Off Center Load
Test verifies that all sections of the Base weigh within specified tolerance.
If the Base does not pass the Off Center Load Test, verify that the Overload Stops are properly
set. (See Section 3.1.)
If the Off Center Load Test cannot be passed, the Load Cell must be adjusted or replaced.
Prior to starting this test, the Base must be connected to a properly functioning Indicator, with
capacity and readability values set according to the specifications for the Base under test.
1. Place test weights equal to one third of the Base's capacity sequentially at each of
the positions A, B, C, and D, as shown in Figure 4-1. Note the Indicator reading at
each position. (For Base capacity, see Table 1-1.)
2. Check the variation between mass weights and indicator reading against specified
Shift Tolerance in Table 1-1.
A
B
C
D
Figure 4-1. Positions A, B, C and D are centered
at each quarter of the base platform.
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