Consideration should be given to locating the calibration photometer in a clean laboratory where
it can be stationary, protected from physical shock, operated by a responsible analyst and used as
a common standard for all field calibrations via transfer standards.
5.3 Pressure Calibration
The pressure sensors are a vital component of the instrument operation and the pressure calibration
should be checked on installation or whenever maintenance is performed.
A thorough leak check must be performed prior to performing a pressure calibration (refer to
Section 6.4.3).
The pressure calibration can either be a two point calibration (one point under vacuum and the other
at ambient pressure) or a single ambient point calibration (when very minor adjustments are required).
Note: Ensure that the instrument has been running for at least one hour before any calibration is
performed to ensure the instrument’s stability. When performing a two point pressure calibration,
it is advisable to perform the vacuum pressure calibration first.
5.3.1 Full Pressure Calibration (Two Point Calibration)
This section outlines how to perform a full pressure calibration. Using the required equipment follow
the steps below to complete a full pressure calibration.
Note: Ensure that the instrument has been running for at least one hour before the calibration is
performed.
Note: Ensure units of measure are the same on both the barometer and instrument.
Equipment Required
• Barometer
• Vacuum source
Procedure
1. Turn OFF the vacuum source and allow the instrument to return to ambient pressure.
2. Disconnect any external tubing connected to the rear of the instrument.
3. Open - Main Menu → Calibration Menu → Pressure Calibration Menu - (read note) - OK.
Note: This action will place the valve sequencing on hold; normal sampling will be interrupted.
4. Edit - Vacuum Set Pt. - (Read displayed instructions) - OK.
5. Connect a barometer to the Sample Port (refer to Figure 102).
Note: It is the user’s responsibility to verify the appropriate transfer standard is chosen and
maintained in accordance with local standards. The exact procedure for certifying an instrument
varies depending on the nature and design of the transfer standard.
To Next Page
Loading...
