Problem In Communicating with PID from PC use VB

Dear All
I am try to coding the program with vb 6.0,but it's still no response from PID. Can you help me to findout the error with the program.Thank you. Bellow is my program.

Dim ValueStr As String

MSComm1.CommPort = 1


MSComm1.Settings = "9600,o,8,1"

MSComm1.InputLen = 8

MSComm1.PortOpen = True

MSComm1.InputMode = comInputModeBinary
Mscomm1.output= ":/01/03/00/8A/00/01/E0/0D/0A"

ValueStr = ""
For i = 1 To 20
ValueStr = MSComm1.Input
Next i
Text1.Text = ValueStr

MSComm1.PortOpen = False