86
Programming the HP E1415 for PID Control
The Operating
Sequence
The HP E1415 has four major operating phases. Figure 3-8 shows these
phases. A trigger event starts the sequence:
1. (INPUT); the state of all digital inputs are captured and each analog
input channel that is linked to an algorithm variable is scanned.
2. (UPDATE); The update phase is a window of time made large
enough to process all variables and algorithm changes made after
INIT. Its width is specified by ALG:UPDATE:WINDOW. This
window is the only time variables and algorithms can be changed.
Variable and algorithm changes can actually be accepted during other
phases, but the changes don’t take place until an ALG:UPDATE
command is received and the update phase begins. If no
ALG:UPDATE command is pending, the update phase is simply used
to accept variable and algorithm changes from the application
program (using ALG:SCAL, ALG:ARR, ALG:DEF). Data acquired
by external specialized measurement instruments can be sent to your
algorithms at this time.
3. (CALCULATE); all INPUT and UPDATE values have been made
available to the algorithm variables and each enabled algorithm is
executed. The results to be output from algorithms are stored in the
Output Channel Buffer.
4. (OUTPUT); each Output Channel Buffer value stored during
(CALCULATE) is sent to its assigned SCP channel. The start of the
OUTPUT phase relative to the Scan Trigger can be set with the SCPI
command ALG:OUTP:DELay.
Reading Running Algorithm Values
The PIDB algorithm stores its most important working values into the
Current Value Table (CVT) each time it executes. Further, by changing the
4
OUTPUT
output table
sent to SCP
channels
4
OUTPUT
output table
sent to SCP
channels
1
INPUT
from SCP
channels,
analog &
digital
1
INPUT
from SCP
channels,
analog &
digital
2
UPDATE
variables &
algorothms
Set by ALG:OUTPUT:DELay (if any)
Trigger Event
Trigger Event
3
EXECUTE ALGS
execute all enabled algorithms
Figure 3-8. Sequence of Loop Operations
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 ...