Section 7. Installation
156
Permission to proceed with a measurement is granted by the measurement
semaphore
(p. 514).
Main scans with measurements have priority to acquire the
semaphore before measurements in a calibration or slow-sequence scan. The
semaphore is taken by the main scan at its beginning if there are measurements
included in the scan. The semaphore is released only after the last instruction in
the main scan is executed.
Slow-Sequence Scans
Slow-sequence scans begin after a
SlowSequence
instruction. They start
processing tasks prior to a measurement but stop to wait when a measurement
semaphore is needed. Slow sequences release the
semaphore
(p. 514)
after complete
execution of each measurement instruction to allow the main scan to acquire the
semaphore when it needs to start. If the measurement semaphore is set by a slow-
sequence scan and the beginning of a main scan gets to the top of the queue, the
main scan will not start until it can acquire the semaphore; it waits for the slow
sequence to release the semaphore. A slow-sequence scan does not hold the
semaphore for the whole of its scan. It releases the semaphore after each use of
the hardware.
WaitDigTrig Scans
Read More
See
Synchronizing Measurements — Details
(p. 387).
Main scans and slow sequences usually trigger at intervals defined by the
Scan()
instruction. Some applications, however, require the main- or slow-sequence scan
to be started by an external digital trigger such as a 5 Vdc pulse on a control port.
The
WaitDigTrig()
instruction activates a program when an external trigger is
detected.
WaitDigTrig()
gives priority to begin a scan, but the scan will execute
and acquire the
semaphore
(p. 514)
according to the rules stated in
Main Scans
(p. 155)
and
Slow-Sequence Scans
(p. 156).
Any processing will be time sliced with
processing from other sequences. Every time the program encounters
WaitDigTrig()
, it will stop and wait to be triggered.
Note
WaitDigTrig()
can be used to program a CR800 to control another
CR800.
Summary of Contents for CR800 Series
Page 2: ......
Page 4: ......
Page 6: ......
Page 32: ......
Page 34: ......
Page 54: ......
Page 92: ......
Page 310: ......
Page 446: ...Section 8 Operation 446 8 11 2 Data Display FIGURE 100 CR1000KD Displaying Data ...
Page 448: ...Section 8 Operation 448 FIGURE 102 CR1000KD Real Time Custom ...
Page 449: ...Section 8 Operation 449 8 11 2 3 Final Storage Data FIGURE 103 CR1000KD Final Storage Data ...
Page 450: ...Section 8 Operation 450 8 11 3 Run Stop Program FIGURE 104 CR1000KD Run Stop Program ...
Page 452: ...Section 8 Operation 452 FIGURE 106 CR1000KD File Edit ...
Page 456: ......
Page 462: ......
Page 523: ...Section 11 Glossary 523 FIGURE 116 Relationships of Accuracy Precision and Resolution ...
Page 524: ......
Page 526: ......
Page 556: ......
Page 558: ......
Page 560: ......
Page 597: ......