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Generating User Defined Functions
function over the entire range would severely impact the accuracy of the
approximation. Remember, the entire range is broken up into only 128
segments of Mx+B operations. If you want accuracy, you MUST limit the
range over which calculations are made. Many transcendental functions are
simply used as a scaling multiplier. For example, a sine wave function is
typically created over a range of 360 degrees or 2*PI radians. After which,
the function repeats itself. It’s a simple matter to make sure the ’x’ term is
scaled to this range before calculating the result. This concept should be
used almost exclusively to obtain the best results.
Haversine Example.
The following is an example of creating a haversine function (a sine wave
over the range of -PI/2 to PI/2). The resulting function represents a fairly
accurate approximation of this non-linear waveform when you limit the
range as indicated. Since the tables must be built upon binary
boundaries(i.e. .125, .25, .5, 1, 2, 4, etc.) and since PI/2 is a number greater
than 1 but less than 2, the next binary interval to include this range will be
2. Another requirement for building the table is that the waveform range
MUST be centered around 0( i.e. symmetrical about the X-axis). If the
desired function is not defined on one side or the other of the Y-axis, then
the table is right or left shifted by the offset from X=0 and the table values
are calculated correctly, but the table is built as though it were centered
about the X-axis. For the most part, you can ignore these last couple of
sentences if it does not make sense to you. The only reason its brought up
here is that your accuracy may suffer the farther away from the X=0 point
you get unless you understand what resolution is available and how much
non-linearity is present in your waveform. We’ll talk about that in the
"Limitations" section, later.
Figure 1 shows the haversine function as stated above. This type of
waveform is typical of the kind of acceleration and deceleration one wants
when moving an object from one point to another. The desired beginning
point would be the location at -PI/2 and the ending point would be at PI/2.
With the desired range spread over +/- PI/2, the 128 segments are actually
divided over the range of +/- 2. Therefore, the 128 Mx+B line segments are
divided equally on both sides of X=0: 64 segments for 0..2 and 64 segments
for -2..0.
Содержание VXI 75000 C Series
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Страница 16: ...16 ...
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Страница 30: ...30 Getting Started Chapter 1 Notes ...
Страница 32: ...32 Field Wiring Chapter 2 Figure 2 1 Channel Numbers at SCP Positions ...
Страница 44: ...44 Field Wiring Chapter 2 Figure 2 11 HP E1415 Terminal Module ...
Страница 54: ...54 Field Wiring Chapter 2 Notes ...
Страница 61: ...Programming the HP E1415 for PID Control 61 Chapter 3 Programming Overview Diagram ...
Страница 124: ...124 Creating and Running Custom Algorithms Chapter 4 Figure 4 2 Algorithm Operating Sequence Diagram ...
Страница 136: ...136 Creating and Running Custom Algorithms Chapter 4 Notes ...
Страница 152: ...152 Algorithm Language Reference Chapter 5 Notes ...
Страница 304: ...304 HP E1415 Command Reference Chapter 6 Command Quick Reference Notes ...
Страница 308: ...308 Specifications Appendix A Thermocouple Type E 200 800C SCPs HP E1501 02 03 ...
Страница 309: ...Specifications 309 Appendix A Thermocouple Type E 200 800C SCPs HP E1508 09 ...
Страница 310: ...310 Specifications Appendix A Thermocouple Type E 0 800C SCPs HP E1501 02 03 ...
Страница 311: ...Specifications 311 Appendix A Thermocouple Type E 0 800C SCPs HP E1509 09 ...
Страница 312: ...312 Specifications Appendix A Thermocouple Type E Extended SCPs HP E1501 02 03 ...
Страница 313: ...Specifications 313 Appendix A Thermocouple Type E Extended SCPs HP E1508 09 ...
Страница 314: ...314 Specifications Appendix A Thermocouple Type J SCPs HP E1501 02 03 ...
Страница 315: ...Specifications 315 Appendix A Thermocouple Type J SCPs HP E1508 09 ...
Страница 316: ...316 Specifications Appendix A Thermocouple Type K SCPs HP E1501 02 03 ...
Страница 317: ...Specifications 317 Appendix A Thermocouple Type R SCPs HP E1501 02 03 ...
Страница 318: ...318 Specifications Appendix A Thermocouple Type R SCPs HP E1508 09 ...
Страница 319: ...Specifications 319 Appendix A Thermocouple Type S SCPs HP E1501 02 03 ...
Страница 320: ...320 Specifications Appendix A Thermocouple Type S SCPs HP E1508 09 ...
Страница 321: ...Specifications 321 Appendix A Thermocouple Type T SCPs HP E1501 02 03 ...
Страница 322: ...322 Specifications Appendix A Thermocouple Type T SCPs HP E1508 09 ...
Страница 323: ...Specifications 323 Appendix A 5K Thermistor Reference SCPs HP E1501 02 03 ...
Страница 324: ...324 Specifications Appendix A 5K Thermistor Reference SCPs HP E1508 09 ...
Страница 325: ...Specifications 325 Appendix A RTD Reference SCPs HP E1501 02 03 ...
Страница 326: ...326 Specifications Appendix A RTD SCPs HP E1501 02 03 ...
Страница 327: ...Specifications 327 Appendix A RTD SCPs HP E1508 09 ...
Страница 328: ...328 Specifications Appendix A 2250 Thermistor SCPs HP E1501 02 03 ...
Страница 329: ...Specifications 329 Appendix A 2250 Thermistor SCPs HP E1508 09 ...
Страница 330: ...330 Specifications Appendix A 5K Thermistor SCPs HP E1501 02 03 ...
Страница 331: ...Specifications 331 Appendix A 5K Thermistor SCPs HP E1508 09 ...
Страница 332: ...332 Specifications Appendix A 10K Thermistor SCPs HP E1501 02 03 ...
Страница 333: ...Specifications 333 Appendix A 10K Thermistor SCPs HP E1508 09 ...
Страница 334: ...334 Specifications Appendix A Notes ...
Страница 346: ...346 Glossary Appendix C Notes ...
Страница 388: ...388 Generating User Defined Functions Appendix F Notes ...
Страница 438: ...438 Index Writing the algorithm 129 values to CVT elements 120 values to the FIFO 121 Z ZERO CALibration ZERO 194 ...