Ranger 7000
®
Series Service Manual
49
Ohaus Corporation www.ohaus.com
4.1.1 OPERATIONAL TEST
1. Connect a functioning Power Adapter to the scale.
2. Plug the Power Cord into a suitable power source.
3. Verify that the scale start up sequence occurs properly. Note any error codes.
4.2 LOAD CELL TEST USING RAMP
To test the Load Cell using RAMP, see Chapter 6.3
.
4.3 PERFORMANCE TESTS
Accurate performance of the Ranger 7000
®
scale s is determined by a series of four performance
tests. The displayed readings are compared with the tolerances listed in Tables 1-1. Tolerance
values are expressed in counts. A one-count difference is shown in the last digit on the scale
display.
The following performance tests are used to evaluate scale operation before and after repairs. The
scale must meet the requirements specified in each test as well as the specifications listed in Table
1-1. Before proceeding with the following tests, the scale should be warmed up (60 minutes) and
calibrated. (See Appendix A).
4.3.1 Precision Test
The Precision Test is a quick test that measures the deviation of a limited number of weight
readings. If the scale passes the precision test than the following tests should be performed.
Note: This is a reference test for approved models (OIML and NTEP). It is not a required test but it
can be used to determine if the scale is working properly.
1. The reading on the display should be 0g.
2. Select a mass weighing near the maximum capacity of the scale, and place it on the center of
the Pan. Observe and record the reading.
3. Remove the mass. The reading should return to 0g ± 1d.
4. Repeat this test three times. The readings should be within ± 1d. If so, the scale passes the
Precision Test.
If the deviation for any set of readings (using the same mass placed on the center of the Pan) is
greater than 1d, the scale does not meet the precision specification. Inspect and correct the
following areas:
-
Check for mechanical obstructions. Any foreign object pressing any part of the moving
assemblies will cause a scale to fail the Precision Test. Inspect and correct as necessary.
-
If the scale does not meet specifications, move it to a suitable location, ensure that it is level,
and try again. If it still does not meet specifications, perform a service calibration, and try
again. (See Appendix B for Service Calibration)
-
If the scale does not pass this test, the Load Cell may need to be replaced.
Summary of Contents for Ranger 7000 R71MHD3
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Page 58: ...Ohaus Corporation www ohaus com 56 Ranger 7000 Series Service Manual 5 1TERMINAL SPARE PARTS...
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