Campbell Scientific CR6 CR6 Measurement and Control System - Page 144

Section 7. Installation Aliasing allows the power of the array to be used with the clarity of unique names. The declared variable name can be used interchangeably with the declared alias in the body of the CRBasic program. However, when a value is stored to finalmemory, the value will have the alias name attached to it. So, if the CRBasic program needs to access that value, the program must use the the alias-derived name. Variables in one, two, and three dimensional arrays can be assigned units. Units are not used elsewhere in programming, but add meaning to resultant data table headers. If different units are to be used with each element of an array, first assign aliases to the array elements and then assign units to each alias. For example: Alias var_array(1) = solar_radiation Alias var_array(2) = quanta Units solar_radiation = Wm-2 Units variable2 = moles_m-2_s-1 7.8.3.5 Declared Sequences Declared sequences include: • DataTable() / EndTable • Sub() / EndSub Certain sequences that may be incidental to a specific application also need to be declared. These include: • ShutDown / ShutdownEnd • DialSequence() / EndDialSequence • ModemHangup() / EndModemHangup • WebPageBegin() / WebPageEnd Declared sequences can be located • prior to BeginProg, • after EndSequence or an infinite Scan() / NextScan and before EndProg or SlowSequence, or • immediately following SlowSequence. SlowSequence code starts executing after any declaration sequence. Only declaration sequences can occur after EndSequence and before SlowSequence or EndProg. 7.8.3.5.1 Data Tables Data are stored in tables as directed by the CRBasic program. A data table is created by a series of CRBasic instructions entered after variable declarations but before the BeginProg instruction. These instructions include: DataTable() 'Output Trigger Condition(s) 'Output Processing Instructions EndTable A data table is essentially a file that resides in CR6 memory. The file is written to each time data are directed to that file. The trigger that initiates data storage is 144