Campbell Scientific CR1000KD CR1000 Measurement and Control System - Page 132

Execution and Task Priority

Page 132 highlights

Section 7. Installation 7.7.3.5.2 Subroutines Read More! See Subroutines (p. 187) for more information on programming with subroutines. Subroutines allow a section of code to be called by multiple processes in the main body of a program. Subroutines are defined before the main program body of a program. Note A particular subroutine can be called by multiple program sequences simultaneously. To preserve measurement and processing integrity, the CR1000 queues calls on the subroutine, allowing only one call to be processed at a time in the order calls are received. This may cause unexpected pauses in the conflicting program sequences. 7.7.3.5.3 Incidental Sequences Data table sequences are essential features of nearly all programs. Although used less frequently, subroutine sequences also have a general purpose nature. The following incidental sequences, however, are used only in applications to which they specifically apply. Shut-Down Sequences The ShutDownBegin / ShutDownEnd instructions are used to define code that will execute whenever the currently running program is shutdown by prescribed means. More information is available in CRBasic Editor Help. Dial Sequences The DialSequence / EndDialSequence instructions are used to define the code necessary to route packets to a PakBus® device. More information is available in CRBasic Editor Help. Modem-Hangup Sequences The ModemHangup / EndModemHangup instructions are used to enclose code that should be run when a COM port hangs up communication. More information is available in CRBasic Editor Help. Web-Page Sequences The WebPageBegin / WebPageEnd instructions are used to declare a web page that is displayed when a request for the defined HTML page comes from an external source. More information is available in CRBasic Editor Help. 7.7.3.6 Execution and Task Priority Execution of program instructions is prioritized among three task sequencers: • Measurement • Digital • Processing 132

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Section 7.
Installation
132
7.7.3.5.2 Subroutines
Read More!
See
Subroutines
(p. 187)
for more information on programming with
subroutines.
Subroutines allow a section of code to be called by multiple processes in the main
body of a program. Subroutines are defined before the main program body of a
program.
Note
A particular subroutine can be called by multiple program sequences
simultaneously. To preserve measurement and processing integrity, the CR1000
queues calls on the subroutine, allowing only one call to be processed at a time in
the order calls are received. This may cause unexpected pauses in the conflicting
program sequences.
7.7.3.5.3 Incidental Sequences
Data table sequences are essential features of nearly all programs. Although used
less frequently, subroutine sequences also have a general purpose nature. The
following incidental sequences, however, are used only in applications to which
they specifically apply.
Shut-Down Sequences
The
ShutDownBegin
/
ShutDownEnd
instructions are used to define code that
will execute whenever the currently running program is shutdown by prescribed
means. More information is available in
CRBasic Editor Help
.
Dial Sequences
The
DialSequence
/
EndDialSequence
instructions are used to define the code
necessary to route packets to a PakBus® device. More information is available in
CRBasic Editor Help
.
Modem-Hangup Sequences
The
ModemHangup
/
EndModemHangup
instructions are used to enclose code
that should be run when a COM port hangs up communication. More information
is available in
CRBasic Editor Help
.
Web-Page Sequences
The
WebPageBegin
/
WebPageEnd
instructions are used to declare a web page
that is displayed when a request for the defined HTML page comes from an
external source. More information is available in
CRBasic Editor Help
.
7.7.3.6 Execution and Task Priority
Execution of program instructions is prioritized among three task sequencers:
Measurement
Digital
Processing