CHAPTER 4 FINAL TESTING
MB23 and MB25 Service Manual
4-1
Ohaus Corporation www.ohaus.com
4.1 FINAL TESTING
Before servicing the MB23 or MB25 Moisture Analyzer, an operational test and various
performance tests should be done to determine if the unit meets specifications. Turn the
Moisture Analyzer on and allow it warm up for at least one hour before performing these tests.
NOTE:
Make sure the test area is free from drafts and the surface the Analyzer rests on
is level and vibration-free. An ASTM Class 1, or OIML Class E2 Tolerance mass
should be used for the performance tests and adjustments.
4.2 Operational Test
Check the Analyzer’s voltage rating, and plug the Power Cord into a suitable power source.
4.3
Segment Display Test
Turn the Moisture Analyzer on, and ensure that all segments are enabled and displayed
briefly. This is a Segment Display Test. (See Figure 4-1.)
Figure 4-1. Segment Display.
4.4 Performance Tests
Accurate performance is determined by a series of three performance tests: Precision, Off-
Center Load and Centered Load. The displayed readings are compared with the tolerances
listed in Table 4-1. Before starting the performance tests, level the Moisture Analyzer.
TABLE 4-1. TYPES OF PERFORMANCE TESTS & TOLERANCES
PERFORMANCE TEST
Tolerance: MB25
Tolerance: MB23
Precision (Std Deviation)
±0.2g
±0.3g
Repeatability (Std Dev)
0.2% (3g sample)
0.05% (10g sample)
0.3% (3g sample)
0.2% (10g sample)
The following performance tests are used to evaluate the Moisture Analyzer operation before
and after repairs. Each Moisture Analyzer tested must meet the requirements specified in each
test as well as the specifications listed in Table 1-1. A Moisture Analyzer which passes each of
these three tests meets the manufacturing specifications.
