OHAUS CKW-55, Service Manual

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CHAPTER 3 INDICATOR TESTING
3.12.1 Span Calibration (Cont.)
3. Press the Yes button to select and perform Span Calibration.....
4. The display flashes 0, indicating that nothing should be placed on the platform at this time.
5. After ensuring that the scale platform is clear, press the Yes button. -C- is displayed while
the zero point is established.
6. After a few seconds, the requested calibration value and unit (based on the Full Scale Capacity
and Calibration Unit setting from the Setup Menu) flashes on the display. A Span Calibration
value based on a Full Scale Capacity and Calibration Unit setting is displayed.
7. If a different Span Calibration value is desired, enter the new value via the numeric keypad.
NOTE : The allowable span range capacity is 1 kilogram or 1 pound to 100% full scale are accepted,
(whole numbers only). Note that values closer to the full span capacity will usually yield the most accurate
calibration.
8. Place the corresponding mass on the platform, then press the Yes button. -C- is momentarily
displayed while the reading is stored.
9. If calibration was successful, the calibration weight is displayed and the scale exits
automatically to the active weighing mode. Remove the weight and begin weighing
operations.
3.12.2 Linearity Calibration
Linearity Calibration uses three points, zero, mid range and full scale. The mid range value can be
optionally changed by the user. Mid-range values closest to 1/2 full scale capacity are recommended to
give the best performance over the entire weighing range. Before calibrating the scale, check that the
weighing base is correctly leveled.
1. Press and hold the G/N/T Menu button until MENU is displayed. When the G/N/T Menu button
is released, CAL is displayed.
2. With CAL displayed, press the Yes button. SPAN is displayed. Press the No button to skip
and proceed to the next sub-menu item LIN.
3. Press the Yes button to select and perform Linearity Calibration. The display flashes 0,
indicating that nothing should be placed on the platform at this time.
4. After ensuring that the scale platform is clear, press the Yes button. -C- is displayed while
the zero point is established. After a few seconds, the requested mid-point calibration value
and unit (based on the Full Scale Capacity and Calibration Unit setting from the Setup Menu)
flashes on the display.