OHAUS TA152, Service Manual

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CHAPTER 4 TESTING
4.1 TESTING
Before and after servicing a Traveler scale, an operational test and various performance tests
should be made to confirm that the scale meets specifications. Allow time for the scale to
stabilize after moving it from an area which is at a different temperature than the area where it is
to be operated. Allow one hour for each 5°F (2.7°C) temperature change before using the
scale. After temperature stabilization, allow an additional 20 minutes after turning the scale on,
for the scale electronics to stabilize.
NOTE:
Make sure the test area is free from drafts and that the scale rests on a level and
vibration-free surface.
4.1.1 Test Masses Required
The masses required to test the Ohaus Traveler scales must meet the requirements of ASTM
Class 4 or OIML F2 Tolerance. The mass values needed for Span and Linearity calibration are
listed in the Specifications Tables 1-1, 1-2, 1-3 and 1-4.
4.2 Operational Test
1. Connect a functioning Power Adapter to the scale power receptacle located on the
bottom of the scale, or install four alkaline AA (LR6) batteries.
2. Plug the Power Cord into a suitable power source.
4.3 Segment Display Test
Turn the scale on, and ensure that all segments are enabled and displayed briefly. The
scale’s model number appears next, followed by a software revision number. This is a
Segment Display Test. Figure 4-1 is a full display test. (See Figure 4-1.)
Figure 4-1. Segment Display
4.4 Performance Tests
Accurate performance of the Traveler scales is determined by a series of three performance
tests. The displayed readings are compared with the tolerances listed in the Specification
Tables in Chapter 1. Tolerance values are expressed in counts. A one-count difference is
shown in the last digit on the scale display.
NOTE:
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 Tables in Chapter 1. Before proceeding with the following tests, the scale
should be calibrated. (See Appendix A.)
Traveler™ Series Scales Service Manual 4-1 Ohaus Corporation www.ohaus.com