[Kovacs]

Hello!

I'm doing a project for school which involves running an experiment with the use of two different programs, E-Prime & LabVIEW, the two of them connected with a TCP/IP connection. E-Prime runs the experiment and LabVIEW gathers data.
Basically what I want to happen is for E-Prime to send a (starting) trigger to LabVIEW, after which LabVIEW will sent a specific response before E-Prime continues again.

E-Prime unfortunately involves some (visual basic) programming of which I have very little knowledge about. This script I found has helped me out quite a bit though:

Dim MySocket As SocketDevice
dim nRead as long
dim inputStr as String
Debug.enabled = true

Set MySocket = New SocketDevice
MySocket.Name = "MySocket"
Dim theSocketDeviceInfo As SocketDeviceInfo
theSocketDeviceInfo.Server = "Rorschach-pc"
theSocketDeviceInfo.Port = 4444
theSocketDeviceInfo.SocketType = ebSocketTypeTcp
theSocketDeviceInfo.ByteOrdering = ebByteOrderingLittleEndian

'Open
MySocket.Open theSocketDeviceInfo


'********Send Trigger *********
MySocket.WriteString "Trigger"
MySocket.FlushOutputBuffer

'*****receive the initial message********

do while MySocket.InputCount = 0
loop

dim initial_response as String

do until MySocket.InputCount = 0
nRead = MySocket.ReadString(inputStr)
initial_response = initial_response & inputStr
loop

debug.print "read from the server: " + initial_response

inputStr = ""

Now the script works fine until the last part.

'*****receive the initial message********
do while MySocket.InputCount = 0
loop

dim initial_response as String

do until MySocket.InputCount = 0
nRead = MySocket.ReadString(inputStr)
initial_response = initial_response & inputStr
loop

debug.print "read from the server: " + initial_response

inputStr = ""

After that I need to rewrite it a little so that E-Prime will only continue after receiving a specific response from LabVIEW (in this case I want it to be "1").
If I keep it the way it is it won't matter whether LabVIEW sends a "1" or "2" response as long as it's one or the other (and that won't do).
I'm pretty sure it involves ReadString and/or initial_response but I just can't figure out the specifics.

I have no clue where to look anymore so any help or advice would be highly appreciated.

[DougT]

I think you need another loop which executes until initial_response = "1"

Perhaps something like

'*****receive the initial message********
do while MySocket.InputCount = 0
loop

dim initial_response as String
do until mid$(initial_response,1,1) = "1"
     do until MySocket.InputCount = 0
     nRead = MySocket.ReadString(inputStr)
          initial_response = initial_response & inputStr
     loop
loop
debug.print "read from the server: " + initial_response

inputStr = ""

The outer loop will continue to execute and ignore the input until the first character of input_response is a 1.

[Kovacs]

Originally Posted by DougT

The outer loop will continue to execute and ignore the input until the first character of input_response is a 1.

Thank you!
It works exactly like you said, but for some reason when it gets the "2" input first, it will not accept the right ("1") input afterwards anymore and gets stuck in an endless loop.
I'll toy around with it a little and see if I can adjust that.

[DougT]

I think that initial_response should be set to Null in the outer loop

'*****receive the initial message********
do while MySocket.InputCount = 0
loop

dim initial_response as String
do until mid$(initial_response,1,1) = "1"
     initial_response = ""
     do until MySocket.InputCount = 0
     nRead = MySocket.ReadString(inputStr)
          initial_response = initial_response & inputStr
     loop
loop
debug.print "read from the server: " + initial_response

inputStr = ""

[Kovacs]

Cheers mate, that's exactly it.
Appreciate the help. =)

[DougT]

Great, good luck with the Project

[Kovacs]

Project is coming along now, but now I'm uncertain if the trigger is actually sent. Using the piece of code below (which is identical to the one in my first post) it would appear that the connection is being established, but the trigger doesn't seem to come through.
I'm trying to find out on which end of the connection things go wrong. With LabVIEW (which is on the other end of the connection) I've created an indicator but the string ("Trigger") I'm sending over never shows up on it.
Might there be something wrong with the Trigger part of the code below, or do I have to look somewhere else?

Dim MySocket As SocketDevice
dim nRead as long
dim inputStr as String
Debug.enabled = true

Set MySocket = New SocketDevice
MySocket.Name = "MySocket"
Dim theSocketDeviceInfo As SocketDeviceInfo
theSocketDeviceInfo.Server = "Rorschach-pc"
theSocketDeviceInfo.Port = 4444
theSocketDeviceInfo.SocketType = ebSocketTypeTcp
theSocketDeviceInfo.ByteOrdering = ebByteOrderingLittleEndian

'Open
MySocket.Open theSocketDeviceInfo


'********Send Trigger *********
MySocket.WriteString "Trigger"
MySocket.FlushOutputBuffer

[DougT]

My guess would be that you need to terminate the "Trigger" command with an "end of message" indicator (eg a Carriage Return line feed pair)

[Kovacs]

Cheers Doug, I really appreciate the help you've been giving me about this (since I know so little about it).
I'm gonna get cracking again.