OHAUS T71P, Service Manual

Page: 19 / 48

CHAPTER 1
GETTING STARTED
7000 Series T71 Indicator Service Manual 1-13 Ohaus Corporation www.ohaus.com
ZErO
O
0.000
lb
ZErO
lb
DONE
ZErO
lb
--C--
1.8 CALIBRATION
Four calibration processes are available: Zero, Span, 3-point Linearity and 5-point Linearity
Calibration. In addition, a Calibration Test and Geographical Adjustment Factor setting are
accessible from the CAL menu.
Preliminary Steps :
1. Be sure appropriate calibration masses are available before beginning calibration.
2. Be sure the scale base is level and stable during the entire calibration process.
3. If LFT is set to On, calibration is unavailable.
To set LFT to OFF, see Section 1.10, page 1-19.
Note: To use the LFT mode again after turning it off, it is necessary to have the
Indicator locked and sealed by local Weights and Measures authorities.
4. If the Calibration Menu is locked in the Menu Lock submenu, turn it back on:
– Press and hold TARE/Menu until MENU LFT OFF appears briefly, followed by MENU
CALIBRATION. Press No until MENU MENU LOCK appears. Press Yes .
– L.MENU RESET appears. Press No . L.MENU LOCK CAL appears. Press Yes .
– L.CAL OFF flashes. Press Yes . Then Press Exit to return to weighing mode.
– Open the Indicator and put the Security Switch on the Main PCB in the OFF position.
5. Allow the Indicator to warm up for approximately five minutes after stabilizing to room
temperature.
6. To abort calibration, press the Exit button anytime during the calibration process.
1.8.1 Zero Calibration
Zero calibration uses one calibration point. The zero calibration point is established with no
weight on the scale. Use this calibration method to adjust for a different pre-load without
affecting the span or linearity calibration.
Press and hold TARE/Menu until LFT OFF flashes and CALIBRATION appears.
Press Yes . CAL ZERO appears. Press Yes .
Note:
If DUAL SCALE is OFF, the ZERO, SPAN, 3PTLIN, 5PTLIN menu items are displayed.
If DUAL SCALE is ON, the ZERO1, ZERO2, SPAN1, SPAN2, 3PTLIN1, 3PTLIN2,
5PTLIN1, 5PTLIN2 menu items are displayed.
With no load on the scale, press Yes to set the new zero point.
The display shows ZERO --C-- , then ZERO DONE and returns to the
current application mode.