TELEVAC MX7M, Инструкция по эксплуатации

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Instruction Manual MX7M Active Gauge
B
.
Gas Type
The MX7M is an indirect pressure sensor and its accuracy will be effected by the presence of
gases other than nitrogen. The MX7M has the ability to apply correction factors for six pre-
defined gases: hydrogen, helium, neon, argon, krypton, and carbon dioxide. These correction
factors have been experimentally determined by Televac to yield the maximum accuracy avail-
able. Conversion factors for use with the MX7M when gases to be measured are other than
Nitrogen are listed. For users wishing to manually apply the conversion, multiply the unit read-
ing by the factor in the table below to convert to the correct pressure reading.
Table 2: Gas Conversion Factors
Gas Type Conversion Factor
Nitrogen 1.00
Hydrogen 2.20
Helium 6.40
Neon 4.10
Argon 0.81
Krypton 0.56
Carbon Dioxide 0.71
C
.
Resolution
The MX7M displays two significant digits by default (low resolution). The user may choose to
operate the gauge in high resolution mode in which the unit will display three significant digits.
The
D . High Voltage Control
The MX7M has an upper range of 1 × 10
− 2
Torr and will be damaged by use above this pressure.
Toggling of the unit on and off can be accomplished via software, through the menu or via
communications, or hardware means, via two pins on the DB-15 connector. For more information
on the difference between hardware and software control, see Section 2.3.
E
.
Diagnostics
The MX7M contains a diagnostic screen for use by Televac service representatives to trou-
bleshoot the unit. The Diagnostic screen contains the FW version of the unit and the date the
software was last revised.
2.6.4 Calibration
To ensure that the unit always displays with the most accuracy, the MX7M includes a number of
operator-configurable calibration points. While the MX7M is factory calibrated, the use of the in-
cluded 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.
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.
To modify the calibration settings:
ˆ
Navigate to the measurement screen.
ˆ
Press SEL three times.
ˆ
Press the UP and DOWN arrows to navigate between panes under the calibration heading.
ˆ
Press ENT to select the calibration point.
email: sales@frederickscompany.com tel: +1 215 947 2500 web: frederickscompany.com mx7m_im rev C 10 of 23