Omega Engineering OMB-1108-0901 사용자 설명서
DaqTemp User’s Manual
10-14-02
Calibration 6-1
Calibration
6
Overview …… 6-1
Using DaqCal.exe …… 6-1
Using DaqCal.exe …… 6-1
Overview
DaqTemp PCI Boards are digitally calibrated at the factory. The digital method involves storing a
correction factor for each range [on the DaqTemp PCI Board] at the time of calibration. Whenever a
particular range is selected, the appropriate calibration constant is automatically applied to a compensating
DAC, thereby calibrating the specific range. The result is that readings generated by the A/D are already
calibrated, and do not require additional processing.
correction factor for each range [on the DaqTemp PCI Board] at the time of calibration. Whenever a
particular range is selected, the appropriate calibration constant is automatically applied to a compensating
DAC, thereby calibrating the specific range. The result is that readings generated by the A/D are already
calibrated, and do not require additional processing.
This is significantly better than calibration methods used by many other products, in which readings are
adjusted in software after they are transferred to the PC. That method reduces the dynamic range of the
A/D, and can adversely affect the speed at which the PC obtains a calibrated reading.
adjusted in software after they are transferred to the PC. That method reduces the dynamic range of the
A/D, and can adversely affect the speed at which the PC obtains a calibrated reading.
The DaqTemp PCI Board offers a user-cal mode, whereby the user can adjust the calibration of the board,
without destroying the supplied factory calibration. This is accomplished by having two distinct calibration
tables in the unit’s on-board EPROM, one which contains the factory calibration factors, and the other
which is available for user calibration.
without destroying the supplied factory calibration. This is accomplished by having two distinct calibration
tables in the unit’s on-board EPROM, one which contains the factory calibration factors, and the other
which is available for user calibration.
Using DaqCal.exe
When calibration adjustments are needed they should be completed in the following order:
1. PGA Input and Output Offset
2. Sample/Hold Offset
3. A/D Offset and Gain
4. VDC Voltage Reference
5. DAC0 Full-Scale
6. DAC1 Full-Scale
7. DAC2 Full-Scale
8. DAC3 Full-Scale
2. Sample/Hold Offset
3. A/D Offset and Gain
4. VDC Voltage Reference
5. DAC0 Full-Scale
6. DAC1 Full-Scale
7. DAC2 Full-Scale
8. DAC3 Full-Scale
A Windows-based program, DaqCal.exe, is used to calibrate Daq systems, including analog expansion
cards. DaqCal.exe is used in conjunction with:
cards. DaqCal.exe is used in conjunction with:
• a 4.5 digit, digital multi-meter
• an adjustable voltage calibrator
• an ambient temperature meter
To use the calibration program:
1. Launch DaqCal.
Note: DaqCal is installed automatically from your data acquisition CD as a part of product
support. This takes place during software installation. DaqCal’s default location is the
Omega DaqX Software folder, in the Programs group.
Omega DaqX Software folder, in the Programs group.
2. When DaqCal opens you will be prompted to select your device from a list. After doing so,
simply follow the illustrated on-screen instructions.