Campbell Scientific CR6 CR6 Measurement and Control System - Page 127
Writing and Editing Programs
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Section 7. Installation 7.8.1 Writing and Editing Programs 7.8.1.1 Short Cut Programming Wizard Short Cut is easy-to-use, menu-driven software that presents lists of predefined measurement, processing, and control algorithms from which to choose. You make choices, and Short Cut writes the CRBasic code required to perform the tasks. Short Cut creates a wiring diagram to simplify connection of sensors and external devices. Quickstart Tutorial (p. 35) works through a measurement example using Short Cut. For many complex applications, Short Cut is still a good place to start. When as much information as possible is entered, Short Cut will create a program template from which to work, already formatted with most of the proper structure, measurement routines, and variables. The program can then be edited further using CRBasic Program Editor. 7.8.1.2 CRBasic Editor CR6 application programs are written in a variation of BASIC (Beginner's Allpurpose Symbolic Instruction Code) computer language, CRBasic (Campbell Recorder BASIC). CRBasic Editor is a text editor that facilitates creation and modification of the ASCII text file that constitutes the CR6 application program. CRBasic Editor is a component of LoggerNet (p. 605), RTDAQ, and PC400 datalogger support software (p. 89). Fundamental elements of CRBasic include the following: • Variables - named packets of CR6 memory into which are stored values that normally vary during program execution. Values are typically the result of measurements and processing. Variables are given an alphanumeric name and can be dimensioned into arrays of related data. • Constants - discrete packets of CR6 memory into which are stored specific values that do not vary during program executions. Constants are given alphanumeric names and assigned values at the beginning declarations of a CRBasic program. Note Keywords and predefined constants are reserved for internal CR6 use. If a user-programmed variable happens to be a keyword or predefined constant, a runtime or compile error will occur. To correct the error, simply change the variable name by adding or deleting one or more letters, numbers, or the underscore (_) from the variable name, then recompile and resend the program. CRBasic Editor Help provides a list of keywords and predefined constants. • Common instructions - instructions (called "commands" in BASIC) and operators used in most BASIC languages, including program control statements, and logic and mathematical operators. • Special instructions - instructions (commands) unique to CRBasic, including measurement instructions, and processing instructions that compress many common calculations used in CR6 dataloggers. These four elements must be properly placed within the program structure. 127