如果你想讓VB和其他軟件或儀器儀表進(jìn)行通訊，就會(huì )經(jīng)常用到數值高低位轉換的問(wèn)題。以下方法可以方便地解決。
一、新建一個(gè)模塊，復制下面代碼。
Option Explicit
' 用途：將二進(jìn)制轉化為十進(jìn)制
Public Function BIN_to_DEC(ByVal Bin As String) As Long
Dim i As Long
For i = 1 To Len(Bin)
BIN_to_DEC = BIN_to_DEC * 2 + Val(Mid(Bin, i, 1))
Next i
End Function
' 用途: 將十進(jìn)制轉化為二進(jìn)制
Public Function DEC_to_BIN(Dec As Long) As String
DEC_to_BIN = ""
Do While Dec > 0
DEC_to_BIN = Dec Mod 2 & DEC_to_BIN
Dec = Dec \ 2
Loop
End Function
' 用途:把數值轉換為高低字節形式
' 輸入：strSendVal(要發(fā)送的數 為整數型),nSendvalh (轉化后的高位),nSendvall (轉化后的低位)
'返回值：nSendvalh,nSendvall
Sub Val2HL(ByVal strSendVal As Long, nSendvalh As Integer, nSendvall As Integer)
Dim strSendValtoBin As String '將發(fā)送的數轉化為二進(jìn)制
Dim strSendValh As String ''二進(jìn)制高位
Dim strSendVall As String ''二制制低位
If strSendVal < 0 Then strSendVal = 32768 - Abs(strSendVal) '小于0 求補
strSendValtoBin = Format(DEC_to_BIN(strSendVal), "0000000000000000")
strSendValh = Mid(strSendValtoBin, 1, 8)
strSendVall = Mid(strSendValtoBin, 9, 8)
nSendvalh = BIN_to_DEC(strSendValh) + 128
nSendvall = BIN_to_DEC(strSendVall)
End Sub
' 用途:把高低字節形式還原為原數值
' 輸入：nSendvalh (轉化后的高位),nSendvall (轉化后的低位)
' 輸出：還原后的數值
Function HL2Val(ByVal nSendvalh As Integer, ByVal nSendvall As Integer) As Long
Dim strSendValtoBin As String '將發(fā)送的數轉化為二進(jìn)制
Dim strSendValh As String ''二進(jìn)制高位
Dim strSendVall As String ''二制制低位
strSendValh = Format(DEC_to_BIN(CLng(nSendvalh) - 128), "00000000")
strSendVall = Format(DEC_to_BIN(CLng(nSendvall)), "00000000")
HL2Val = BIN_to_DEC(strSendValh & strSendVall)
End Function
二、調用舉例
1、把數值轉換為高低字節形式
Dim H As Integer, L As Integer, V As Long
V = 1200
Val2HLV, H, L
Debug.Print H, L (H=132,L=176)
2、把高低字節形式還原為原數值
Dim H As Integer, L As Integer, V As Long
H=132
L=176
V=HL2Val(H,L) (V=1200)
