Appendix D
Measurement Speed and Accuracy Tradeoffs
The HP E1326B SCPI driver was designed so that its default mode of
operation will deliver high accuracy readings with a minimum of
programming effort. However, many applications require high-speed
measurements and reduced reading accuracy is acceptable.
The following guidelines show how to increase measurement speed.
Be aware that these guidelines also increase the complexity of the program.
1. Avoid function changes.
2. Avoid aperture changes.
3. Minimize the number of command/response sessions.
4. Do binary transfers to the computer:
REAL 32 is fastest and is compatible with compiled languages.
REAL 64 is fast and is compatible with HP BASIC.
5. Use macros to minimize command parsing time.
6. Set autozeroing to ONCE or OFF.
7. Turn auto ranging OFF.
8. Decrease aperture time:
to reach 10
µ
s aperture time you must be on a fixed range.
9. Store the readings in command module RAM instead of sending
them directly to the computer.
10. Post process strain and temperature measurements.
Note
Only items 7 and 8 may reduce the accuracy of a measurement. The rest of
the guidelines involve increased work for the system programmers.
Appendix D
Measurement Speed and Accuracy Tradeoffs 269
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