好久没回来了,请大家帮忙看下这个发送语句怎么写? 散分50.

[szywelcome]

ex) When reading the D-Register from PV(D0001) to SP(D0002)
- Transmission : [stx]01RSD,02,0001[cr][lf]
- Transmission (Include Check Sum) : [stx]01RSD,02,0001C5[cr][lf]
If received data are PV=50.0 and SP=30.0, the result is as under;
- Reception : [stx]01RSD,OK,01F4,012C[cr][lf]
- Reception (Include Check Sum) : [stx]01RSD,OK,01F4,012C19[cr][lf]
※The converting process for display received hexadecimal PV value.
①. Converting decimal : 01F4 (Hexadecimal) 500(Decimal)
②. Result × 0.1 : 500 * 0.1 50.0
[stx]=0x02
[cr]=0x0D
[lf]=0x0A

根据上面的值我写了一条发送数据Transmission : [stx]01RSD,02,0001[cr][lf]

0x0201RSD,02,00010x0D0x0A .这样把值直接写进去有错吗,还是要用逗号分开.
MSComm1.Output="0x0201RSD,02,00010x0D0x0A"
发送数据有反应,但没返回数据.
现在程序和接线都是正确的,就是命令发了过去没返回数据.
请问这条输出命令根据上面的提示该怎么写?

[szywelcome]

Transmission : [stx]01RSD,02,0001[cr][lf]
发送上面的数据格式,是字符串形式还是数组形式.

[zdingyun]

你的命令应按以下方式发送:

Private Sub CmdSend_Click()
    Dim sj As String 
    Dim i As Integer 
    Dim sum As Integer 
    Dim sumStr As String 
    sj = "01RSD,02,0001" 
    Text1 = sj 
    For i = 1 To Len(sj) 
        sum = sum + Asc(Mid(sj, i, 1)) 
    Next 
    sumStr = Hex(sum Mod 256) 
    MsComm1.Output = Chr(2) & sj & sumStr & Chr(&HD) & Chr(&HA) '这是有校验和的
End Sub 

如果无校验和则:

Private Sub CmdSend_Click()
    Dim sj As String 
    Dim i As Integer 
    Dim sum As Integer 
    Dim sumStr As String 
    sj = "01RSD,02,0001" 
    Text1 = sj 
    For i = 1 To Len(sj) 
        sum = sum + Asc(Mid(sj, i, 1)) 
    Next 
    sumStr = Hex(sum Mod 256) 
    MsComm1.Output = Chr(2) & sj &  Chr(&HD) & Chr(&HA) 
End Sub 

[zdingyun]

以上代码依据:
NOVA Series
Communication Manual
Communication with sum check, the ASCII codes of the text between STX and before checksum are
converted into hexadecimal values and added on a byte basis.
Then the lowermost byte of the added results is turned into ASCII code, and its lower byte is used as the
checksum.(Lower 2 bytes)

[kingsang]

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