122
Creating and Running Custom Algorithms
ALG3 etc.
Using ALG_NUM allows you to write identical code that can take different
actions depending on the name it was given when defined.
Calling User
Defined Functions
Access to user defined functions is provided to avoid complex equation
calculation within your algorithm. Essentially what is provided with the
HP E1415 is a method to pre-compute user function values outside of
algorithm execution and place these values in tables, one for each user
function. Each function table element contains a slope and offset to calculate
an mx+b over the interval (x is the value you provide to the function). This
allows the DSP to linearly interpolate the table for a given input value and
return the function’s value much faster than if a transcendental function’s
equation were arithmetically evaluated using a power series expansion.
User functions are defined by downloading function table values with the
ALG:FUNC:DEF command and can take any name that is a valid ’C’
identifier like ’haversine’, ’sqr’, ’log10’ etc. To find out how to generate table
values from your function equation, see "Generating User Defined
Functions" in Appendix F page 367. For details on the ALG:FUNC:DEF
command, see page 176 in the Command Reference.
User defined functions are global in scope. A user function defined with
ALG:FUNC:DEF is available to all defined algorithms. Up to 32 functions
can be defined in the HP E1415. You call your function with the syntax
<func_name>(<expression>). Example:
for user function pre-defined as square root with name ’sqrt’
O108 = sqrt( I100); /* channel 8 outputs square root of input channel 0’s value */
NOTE
A user function must be defined (ALG:FUNC:DEF) before any algorithm is
defined (ALG:DEF) that references it.
A C-SCPI program that shows the use of a user defined function is supplied
on the examples disc in file "tri_sine.cs". Appendix G page 389 for example
program listings.
Operating Sequence
This section explains another important factor in your algorithm’s execution
environment. Figure 4-2 shows the same overall sequence of operations that
you saw in Chapter 3, but also includes a block diagram to show you which
parts of the HP E1415 are involved in each phase of the control sequence.
Overall Sequence
Here, the important things to note about this diagram are:
•
All algorithm referenced input channel values are stored in the
Summary of Contents for VXI 75000 C Series
Page 2: ......
Page 16: ...16 ...
Page 18: ......
Page 30: ...30 Getting Started Chapter 1 Notes ...
Page 32: ...32 Field Wiring Chapter 2 Figure 2 1 Channel Numbers at SCP Positions ...
Page 44: ...44 Field Wiring Chapter 2 Figure 2 11 HP E1415 Terminal Module ...
Page 54: ...54 Field Wiring Chapter 2 Notes ...
Page 61: ...Programming the HP E1415 for PID Control 61 Chapter 3 Programming Overview Diagram ...
Page 136: ...136 Creating and Running Custom Algorithms Chapter 4 Notes ...
Page 152: ...152 Algorithm Language Reference Chapter 5 Notes ...
Page 304: ...304 HP E1415 Command Reference Chapter 6 Command Quick Reference Notes ...
Page 308: ...308 Specifications Appendix A Thermocouple Type E 200 800C SCPs HP E1501 02 03 ...
Page 309: ...Specifications 309 Appendix A Thermocouple Type E 200 800C SCPs HP E1508 09 ...
Page 310: ...310 Specifications Appendix A Thermocouple Type E 0 800C SCPs HP E1501 02 03 ...
Page 311: ...Specifications 311 Appendix A Thermocouple Type E 0 800C SCPs HP E1509 09 ...
Page 312: ...312 Specifications Appendix A Thermocouple Type E Extended SCPs HP E1501 02 03 ...
Page 313: ...Specifications 313 Appendix A Thermocouple Type E Extended SCPs HP E1508 09 ...
Page 314: ...314 Specifications Appendix A Thermocouple Type J SCPs HP E1501 02 03 ...
Page 315: ...Specifications 315 Appendix A Thermocouple Type J SCPs HP E1508 09 ...
Page 316: ...316 Specifications Appendix A Thermocouple Type K SCPs HP E1501 02 03 ...
Page 317: ...Specifications 317 Appendix A Thermocouple Type R SCPs HP E1501 02 03 ...
Page 318: ...318 Specifications Appendix A Thermocouple Type R SCPs HP E1508 09 ...
Page 319: ...Specifications 319 Appendix A Thermocouple Type S SCPs HP E1501 02 03 ...
Page 320: ...320 Specifications Appendix A Thermocouple Type S SCPs HP E1508 09 ...
Page 321: ...Specifications 321 Appendix A Thermocouple Type T SCPs HP E1501 02 03 ...
Page 322: ...322 Specifications Appendix A Thermocouple Type T SCPs HP E1508 09 ...
Page 323: ...Specifications 323 Appendix A 5K Thermistor Reference SCPs HP E1501 02 03 ...
Page 324: ...324 Specifications Appendix A 5K Thermistor Reference SCPs HP E1508 09 ...
Page 325: ...Specifications 325 Appendix A RTD Reference SCPs HP E1501 02 03 ...
Page 326: ...326 Specifications Appendix A RTD SCPs HP E1501 02 03 ...
Page 327: ...Specifications 327 Appendix A RTD SCPs HP E1508 09 ...
Page 328: ...328 Specifications Appendix A 2250 Thermistor SCPs HP E1501 02 03 ...
Page 329: ...Specifications 329 Appendix A 2250 Thermistor SCPs HP E1508 09 ...
Page 330: ...330 Specifications Appendix A 5K Thermistor SCPs HP E1501 02 03 ...
Page 331: ...Specifications 331 Appendix A 5K Thermistor SCPs HP E1508 09 ...
Page 332: ...332 Specifications Appendix A 10K Thermistor SCPs HP E1501 02 03 ...
Page 333: ...Specifications 333 Appendix A 10K Thermistor SCPs HP E1508 09 ...
Page 334: ...334 Specifications Appendix A Notes ...
Page 346: ...346 Glossary Appendix C Notes ...
Page 388: ...388 Generating User Defined Functions Appendix F Notes ...