TELEVAC MX7B, Instruction Manual

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6.4 Calibration
6.4.1 To ensure that the unit always displays with the most accuracy, the MX7B includes a number of
operator-configurable calibration points. While the MX7B is factory calibrated, the use of the
included calibration points may become necessary after extended use, contamination, etc. If
accuracy is critical, it is recommended to return the sensor to Televac® for NIST-traceable
calibration.
6.4.2 The unit should only be calibrated when under vacuum and a NIST-traceable calibrate reference
is available. Any change of calibration values by the customer voids any Televac® calibration and
should only be used in when in line with a defined quality system.
6.4.3 To modify the calibration settings:
6.4.3.1 Navigate to the measurement screen.
6.4.3.2 Press SEL three times.
6.4.3.3 Press the UP and DOWN arrows to navigate between panes under the calibration
heading.
6.4.3.4 Press ENT to select the calibration point.
6.4.3.5 Press UP or DOWN until the unit matches the reference in use for calibration.
6.4.3.6 Press ENT to save the adjustment. Press SEL to exit without saving.
6.4.3.7 Note 1: Calibration should be performed in the following order: 1*10 − 6 Torr adjustment,
1*10 − 5 Torr adjustment, 1*10 − 4 Torr adjustment, 1*10 − 3 Torr adjustment. Failing to
calibrate -in this order will result in inaccuracies.
6.4.3.8 Note 2: Changing calibration settings voids NIST-Traceable calibrations!
6.4.4 10 -6 Torr
6.4.4.1 The 1*10
− 6
calibration point allows the gauge to adjust the pressure reading at 1*10
− 6
Torr. This calibration point should not be used to adjust the gauge reading below a
reference pressure of 5*10 − 7 Torr or above 5*10 − 6 Torr.
6.4.5
10
-5
Torr
6.4.5.1 The 1*10 − 5 calibration point allows the gauge to adjust the pressure reading at 1*10 − 5
Torr. This calibration point should not be used to adjust the gauge reading below a
reference pressure of 5*10 − 6 Torr or above 5*10 − 5 Torr.
6.4.6 10 -4 Torr
6.4.6.1 The 1*10
− 4
calibration point allows the gauge to adjust the pressure reading at 1*10
− 4
Torr. This calibration point should not be used to adjust the gauge reading below a
reference pressure of 5*10 − 5 Torr or above 5*10 − 4 Torr.
6.4.7 10 -3 Torr
6.4.7.1 The 1*10 − 3 calibration point allows the gauge to adjust the pressure reading at 1*10 − 3
Torr. This calibration point should not be used to adjust the gauge reading below a
reference pressure of 5*10 − 4 Torr or above 1*10 − 3 Torr.
6.4.8 Analog Output Adjustment
6.4.8.1 The MX7B allows for an offset calibration of the MX7B to provide maximum accuracy for
users where long cable lengths are affecting the accuracy. To calibrate the analog
output, adjust the pressure of the vacuum system to a stable pressure corresponding to
the value near the maximum analog output. Measure the analog output with a volt
meter, compare the displayed pressure on the gauge to the calculated pressure based
on the analog output, and adjust the calibration until the displayed pressure and
calculated pressure match. See section 7.