關(guān)于VB的MSComm串口接收兩次,Time事件 10分
如下:(1)和(2)單獨用按鈕命令可以正常執行..用Timer1執行1和Timer2執行2,收回來(lái)的數據就很亂..把(1)(2)都寫(xiě)到Timer1下面下,收回來(lái)的數據也亂..是不是輸入輸出緩沖區兩個(gè)混亂
Private Sub Timer1_Timer() '時(shí)鐘事件,間隔設定Interval毫秒就執行一次
(1)DIM SENTDATA AS STRING,,Dim getdata
MSComm1.InBufferCount = 0 '清空接收緩沖區
MSComm1.OutBufferCount = 0 '清空發(fā)送緩沖區
MSComm1.Output = 讀取數據指令
Do
DoEvents
Loop Until MSComm1.InBufferCount >= 20 'PLC應該返回8個(gè)字符 固定的4+2*N
'一個(gè)起始符+一個(gè)寄存器(有兩個(gè)字節)(每個(gè)字節=2字符)+一個(gè)結束符+兩個(gè)校驗和
getdata = MSComm1.Input
Text1.Text = getdata ''返回的低字節在前,高在后
(2)Dim sendat As String,,Dim getdat
MSComm1.InBufferCount = 0
MSComm1.OutBufferCount = 0
MSComm1.Output =讀取數據指令
Do
DoEvents
Loop Until MSComm1.InBufferCount >= 8
getdat = MSComm1.Input
Text4.Text = getdat ''返回的低字節在前,高在后