Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 272)

Section 7. Creating and Editing Datalogger Programs
The first line of text identifies the type of datalogger program to be written.
This is followed by a comment line and the Program Table Headers and
Execution Interval fields. The Program Table Headers and Execution Interval
fields are protected text that cannot be deleted or commented out. (The asterisk
is used to identify the beginning of a program table in the datalogger.) When
the cursor is moved to the Execution Interval line, the field for the execution
interval is highlighted. A numeric value must be entered or the instructions in
the table will never be executed.
Instructions inserted under the Program Table 1 header will be run based on the
execution interval for that table. Likewise, instructions inserted under the
Program Table 2 header will be run based on the execution interval for Program
Table 2. Program Table 3 is reserved for subroutines that are called by either of
the other tables. Most users find they can write the entire program in Program
Table 1, avoiding complications associated with synchronizing two tables.
Program Table 2 is normally used only when portions of the program require a
different execution interval (placed in Program Table 2).
Program tables in this section refer strictly to sections of the
datalogger program. Do not confuse these program sections with
the data tables created in table-based dataloggers using P84 to
store output data.
When the program is complete, select File | Save from the Edlog menu. A
standard file dialog box will appear in which to type a file name. Edlog
supports long file names for the datalogger programs. Use descriptive names
to help document the program’s function. After saving the file, you will be
prompted to compile the program. When a program is compiled the code will
be checked for errors. After compiling, the datalogger program can be sent to
the datalogger using the Connect Screen.
7.4.2.1 Program Structure
While Edlog is not a structured programming language there are some standard
programming practices that will help you and others understand what the
datalogger program is intended to do.
Comments – Edlog provides the ability to add comments on any blank line
and to the right of all instructions. Liberal use of descriptive comments makes
the program clearer and will help you remember what you were doing when
you come back to it a year or two later. Especially useful are descriptions of
what sensors are connected and how they are wired to the datalogger.
Program Flow – It is easier to follow a program that is written in distinct
sections, each of which handles a specific type of instruction. The
recommended sequence is:
− Measure Sensors – In this first section put all the instructions that get data
from the sensors attached to the datalogger. The sensor readings are stored
in input locations, ready for the next section.
− Process Measurements – In this section do all the calculations and data
processing to prepare the data for output.
NOTE
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