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Logging multiple serial devices that burst data

erehm Sep 9, 2023 12:36 AM

I'm looking to log data for four RS-232 serial devices that will burst data (CR/LF terminated ASCII strings)  at 1 Hz for 10 seconds every XX minutes, where XX is probably 15. On each serial device, I can specify data rate (1 Hz), burst size (10 samples), and burst interval (15 min = 900 s).  The devices are not synchronized.

Inelegant solution:  Starting wtih just one sensor, I scan continuously a 1 Hz and test the value NBytesReturned from SerialInRecord. (NBytesReturned is guaranteed to be >= 42 if the sensor has valid output.)  So, I conditionally CallTable based on the value of NBytesReturned. 

The nice thing about this is that I don't have to change any code should I change the burst interval on any device.

This works reliably,  I think I can do the same trick in the Main program with the other devices inside the same Scan loop.  But is there a more elegant solution?    

-- Eric


DataTable (EcoTriplet,1,-1) 'Set table size to # of records, or -1 to autoallocate.
   Sample (1,Chl470,Long)
   Sample (1,Beta700,Long)   
   Sample (1,FDOM,Long)
   Sample (1,RawString,String) 

'Define Subroutines
'EnterSub instructions here

'Main Program
  SerialOpen (PortEco,19200,0,0,200,0)
  Scan (1,Sec,3,0)
    'Each Eco record is a tab-delimited string of 42-48 bytes plus :
    '99/99/99	99:99:99	695	xx38	700	xx49	460	xx41	999
     SerialInRecord (PortEco,RawString,&h0A,0,&h0D,NBytesReturned,01)   
    'Get counts for each measurement by splitingt string at tabs CHR(09)
    SplitStr (SplitStrings(1),RawString,CHR(09),9,5)
    Chl470=SplitStrings(4)      'xx38, where xx are additional digits
    Beta700=SplitStrings(6)     'xx49
    FDOM=SplitStrings(8)        'xx41
    'Update table
    If NBytesReturned >= 42 Then
      CallTable EcoTriplet



lillianthomas Sep 29, 2023 04:42 AM

This post is under review.

erehm Oct 12, 2023 12:54 AM


JDavis Oct 19, 2023 05:56 PM

I think your program is about as simple as can be to get the job done. By definition of many programmers, that is elegant.

We can add complexity to do smarter data processing. If for example you want all 10 FDOM measurements from a burst in the same record, that is possible. It will take quite a bit more logic in the program. It could also be done in more than one way.

You would need arrays to hold the data values (ex. FDOM(10) ). You also need a start machine that picks up on the start of a burst, and the end of a burst. If there is something like a burst number in the data format, you could watch that. Without something in the data format to watch, you need a timer to know the burst is done.

taniyuki Nov 2, 2023 04:15 AM

This post is under review.

Finley Nov 2, 2023 07:20 AM

This post is under review.

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