OHAUS EB SERIES, Service Manual

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CHAPTER 4 FINAL TESTING & CALIBRATION
EB Series Scales Service Manual 4-1 Ohaus Corporation www.ohaus.com
4.1 PERFORMANCE TESTS
Accurate performance of the EB Series Scales is determined by a series of three performance
tests, Repeatability Test, Off-Center Load Test and Linearity Test. These tests are used to
evaluate the scale performance before and after repairs. Each scale tested must meet the
requirements specified in each test as well as the specifications listed in Table 4-1. A scale
passing each of these three tests complies with Ohaus specifications. A segment display test
determines if the display is working properly.
4.1.1 Segment Display Test
Connect the AC Adapter into a suitable power source and connect it to the scale. Turn the scale
on, all 999999 segments are displayed followed by a countdown of 8's, 7's, 6's and so on until
all zeros are reached briefly followed by a software revision number. This is a segment display
test. Figure 4-1 illustrates the starting of the display test.
Figure 4-1. Segment Display.
4.1.2 Repeatability Test
Repeatability is the Standard Deviation of a set of similar weight readings.
Requirements:
To perform this test a single mass must be used for all readings.
The test mass should be approximately 1/2 of the capacity of the scale.
Before starting a repeatability test, set up the scale as follows:
Set Up:
Enter the menu and adjust and record the following setting.
A. Set the Filter level to 1.
B. Set the AZT (Auto Zero Tracking) to 1d.
C. Set the scale to display the same units as the performance specifications.
D. Set the Zero return to 0.
Record Settings:
Filter Level Setting = ____________
Auto Zero Tracking Setting = ____________
Displayed Units = ____________
Zero Return = ____________
Mass Used = ____________