Fluke RUSKA 7750i, Руководство пользователя, Страница: 77 / 106

Maintenance
Calibration
6
6-3
Processor Battery
The processor board uses a lithium battery to maintain time and date information. This
battery has a varying life. If the instrument is left on 24 hours a day, it may last 5 to 10
years. If the instrument is stored, it may only last one year. Annual replacement is
recommended. To replace the battery:
1.
Turn off power and remove the instrument cover. (See Chapter 6, Removing the
ADTS’s Cover)
2. Remove the processor card by removing the screw and the bracket that locks the
display cable in place and gently rock the card upward.
3. Holding the processor card, remove the battery (the round silver object), by carefully
pulling on the battery.
4. Plug in a new battery (part number 4-725).
5. Reinstall the processor card, the bracket that locks the display cable in place and the
screw. Replace the instrument cover.
6. The time and date may have to be re-entered. See Chapter 4, Menu | Setup – System.
Calibration
To keep the ADTS operating within its specified precision, the calibration procedure
described below should be performed once every year. If a higher level of overall
performance is desired, the user can calibrate more frequently.
Note
The calibration procedure automatically generates coefficients that are
stored in memory on the ADTS. If these constants are “lost” for any reason,
the calibration procedure must be performed, regardless of the last
calibration date. If the calibration coefficients have been recorded, they
may be restored to the ADTS at any time by “editing the coefficients.”
(Chapter 6, Editing the Calibration Coefficients).
Calibration Instructions
To calibrate the ADTS, the user connects a calibration standard such as the
RUSKA Model 2465 or 2468 Gas Piston Gauge to the ADTS’s test port, then follow the
multi-step calibration procedure on the ADTS’s display. No disassembly is required and
there are no potentiometers to tune.
Note
The uncertainty of the final calibration must include the uncertainty of the
pressure standard being used.
Preparation
1. When calibrating the Qc channel, verify that the Ps Test Port is open to atmosphere
and that the calibration standard is connected to the Pt Test Port. When calibrating
the Ps channel, verify that the calibration standard is connected to the Ps test port.
2. Verify that the ADTS has been at stable environmental temperature and that the oven
temperature (MENU | MENU | DISPLAY | TEMPERATURE) has been stable for at
least three hours.
3. Verify that the ADTS is in Measure mode (Chapter 4).
4. If desired, change the ADTS’s engineering units of measure (Chapter 4) to match
those of the calibration standard.