Signature (Program Code Signature)

The Signature function returns the signature for program code in a datalogger program.

Syntax

Signature

'code for which to calculate signature

variable = Signature

The following program shows the use of the Signature function to return a unique signature for two portions of the program code.

Public Sig(2), RefTemp, TCTemp, Counter AS Long

BeginProg
  Scan (1,Sec,3,0)
    Signature
    PanelTemp (RefTemp,15000)
    TCDiff (TCTemp,1,mv200C,U1,TypeT,RefTemp,True,0,15000,1.0,0)
    
    Sig(1) = Signature
  NextScan

  SlowSequence
  Signature
  Do
    Counter=Counter+1
    If Counter = 99999 Then Counter = 0
    Sig(2)=Signature
  Loop
EndProg

Remarks

The Signature function returns a number between 0 and 65535 that is a Campbell Scientific pseudo random signature of the program code and then reinitializes the signature seed to &HAAAA (43690). Signature must occur within BeginProg/EndProg statements, or within a subroutine. The portion of code for which to return a signature is bracketed by two signature declarations. This function is not used until it is called in the program; therefore, the first use will always return 43690. More than one Signature function can be used in the program. This function allows a way to detect whether or not portions of the program code have changed. Blank lines and comments are not included in the Signature.