Campbell CR850, Руководство оператора

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Section 7. Installation
207
SerialOutBlock()
1,3
•
Binary
•
Can run in pipeline mode inside the digital measurement task (along with
SDM instructions) if the
COMPort parameter is set to a constant argument
such as
COM1
or
COM2
, and the number of bytes is also entered as constant.
SerialOut()
•
Handy for ASCII command and a known response, e.g., Hayes-modem
commands.
•
Returns 0 if not open, else the number of bytes sent
SerialInRecord() 2
•
Can run in pipeline mode inside the digital measurement task (along with
SDM instructions) if the
COMPort parameter is set to a constant argument
such as
COM1
or
COM2
, and the number of bytes is also entered as a constant.
•
Simplifies synchronization with one way.
•
Simplifies working with protocols that send a "record" of data with known
start and/or end characters, or a fixed number of records in response to a poll
command.
•
If a start and end word is not present, then a time gap is the only remaining
separator of records. Using
COM1
or
COM2
coincidentally detects a time gap
of >100 bits if the records are less than 256 bytes.
•
Buffer size margin (one extra one byte).
1 Processing instructions
2
Measurement instruction in the pipeline mode
3
Measurement instruction if expression evaluates to a constant
7.8.8.5.2 Input Programming Basics
Applications with the purpose of receiving data from another device usually
include the following procedures. Other procedures may be required depending on
the application.
1. Know what the sensor supports and exactly what the data are. Most sensors
work well with TTL voltage levels and RS-232 logic. Some things to
consider:
•
Become thoroughly familiar with the data to be captured.
•
Can the sensor be polled?
•
Does the sensor send data on its own schedule?
•
Are there markers at the beginning or end of data? Markers are very useful
for identifying a variable length record.
•
Does the record have a delimiter character, e.g. ",", spaces, or tabs? These
delimiters are useful for parsing the record into usable numbers.