OHAUS Valor 1000, Руководство по обслуживанию

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CHAPTER 4 TESTING
Valor 1000 Series Service Manual 20 Ohaus Corporation www.ohaus.com
4.2.1 Precision Test
The Precision Test measures the Standard Deviation of a set of similar weight readings, which
should match the specification for each model, listed in Table 1-1, Table 1-2 and Table 1-3.
Power on the balance. The reading on the display should be 0g.
Select a mass weighing near the maximum capacity of the balance, and place it on the center of
the Pan. Observe and record the reading.
Remove the mass. The reading should return to 0g ±1 count.
Repeat this test three times. The reading should be within ±1 count of the reading recorded. If
so, the balance 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 ±1 d, the balance does not meet the precision specification. Inspect and correct
the following areas:
Check for mechanical obstructions. Any foreign object touching any part of the moving
assemblies will cause a balance 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 A for Service Calibration.)
4.2.2 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 ½ of the capacity of the instrument.
– Wear gloves when handling the mass.
Before starting a repeatability test, set up the instrument as follows:
Set Up:
Follow the steps in Appendix A, Setup and Calibration.
Record Settings:
Zero Tracking Setting = ____________
Displayed Units = ____________
Mass Used = ____________