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I was trying to replicate the 2-register Modbus long integer behavior by constructing a 32-bit integer from two 16-bit words.

[CR-6 Firmware: CR6.Std.12.00 CR6-WIFI.05.03]

Example:

High Word:    100   0x0064       00000000 01100100
Low Word:     200   0x00C8       00000000 11001000

Combined: 6553800   0x006400C8   00000000 01100100 00000000 11001000

 We can quickly code up a function to handle this conversion:

Public highword As Long, lowword As Long, test As Long

Function highlow(hi As Long, lo As Long)
  Dim holder As Long
  holder = 0
   MoveBytes (holder,0,hi,2,2,0)
   MoveBytes (holder,2,lo,2,2,0)
   'or holder += lo
  Return holder
End Function

'Main Program
BeginProg
  Scan (1,Sec,3,0)
    test = highlow(highword, lowword)
  NextScan
EndProg

 This seems to work well, but falls apart on larger integer words:

Broken Example:

High Word:  20000     0x4E20      01001110 00100000
Low Word:   11467     0x2CCB      00101100 11001011

Combined: 1310731467  0x4E202CCB  01001110 00100000 00101100 11001011

However, function returns: 1310731520 0x4E202D00 01001110 00100000 00101101 00000000

Difference:
01001110 00100000 00101100 11001011 - 1310731467
01001110 00100000 00101101 00000000 - 1310731520
01001110 00100000 0010110X XXXXXXXX - -53

 This fails on the last 9 or 10 bits. And it happens whether I move bytes, add the low word to the shifted high word, or initially assign the value of holder to the low word.

This is massively confusing as 20000 shifted 16 bits left = 1310720000 and the logger can handle the calculation of 1310720000 + 11467 correctly. Why is it missing on:

holder = 0
MoveBytes (holder,0,hi,2,2,0)
holder += lo

 Thanks!