VBA ReadString error

[miclausig90]

Hey everyone. I'm Andrea, a technician who just started working with a Fluke 8845a which needs to be controlled by an Excel file to measure resistance every "x" seconds.

Now, I'm really just beginning. And I'm already in trouble. When inserting the code below  in VBA I get the error attached. The error pops up at the ReadString line.

It says "runtime timeout, automation error". What can it be?

P. S. Sorry if there is a presentation section, I'm from mobile and I couldn't find it.

[code]
Sub idn()
Dim ioMgr As VisaComLib.ResourceManager
Dim idn
Dim instrument As VisaComLib.FormattedIO488
Set ioMgr = New VisaComLib.ResourceManager
Set instrument = New VisaComLib.FormattedIO488
' use instrument specific address for Open() parameter – i.e. GPIB0::22
Set instrument.IO = ioMgr.Open("TCPIP0::192.168.1.6::5025::SOCKET")
instrument.WriteString ("*IDN?")
instrument.WriteString "SYSTem:REMote"
instrument.WriteString ("READ?")
idn = instrument.ReadString

End Sub

[/code] 

[cymrieg]

For a socket connection, you need to send every command with a linefeed at the end ('\n') and then for the Reads you need to enable TermChar:

instrument.IO.TerminationCharacterEnabled = true

Make sure the termination character in the Fluke is linefeed as this is the default for Visa. If different then you need to set this also.

[miclausig90]

Hi and thank you.

My Fluke seems to receive the commands I'm sending because it gets in remote. It's reading that causes the issue. Also, all I need to had is "\n" at the end of every command I send and "\n" when reading? 

[Minions]

---

@miclausig90 wrote:

instrument.WriteString ("*IDN?")
instrument.WriteString "SYSTem:REMote"
instrument.WriteString ("READ?")
idn = instrument.ReadString

---

Typically, a newline "\n" should be appended to each WriteString function.  Be aware that you have requested two separate pieces of data from the instrument.  The first is for the instrument identification string (*IDN?) while the other is for some unknown data (READ?) that may or may not reside within the instrument buffer.  If an error occurs, then maybe it is because nothing currently exists within the buffer to read or this program has been repetitively called and forced an overflow in the response buffer.

[miclausig90]

Ok, I got what you mean about the READ error. Only thing I don't understand is "a newline "\n" should be appended to each WriteString function". You literally mean another line by pressing enter? Or can you make an example, please? 

[cymrieg]

When you start sending data (commands) to the instrument it will go into remote mode but most instruments (SCPI) won't parse (execute that command) until it knows it has received a "complete command" Now on GPIB, USBTMC, LAN (VXI-11 and HiSLIP) there is a handshake that lets an instrument know the command has been completely sent. For RS232 and LAN - Raw Socket there is no handshake so the instrument is waiting to see a Linefeed and vice versa for the PC receiving data back from the instrument.

So for C# you should send this

instrument.WriteString("*idn?\n")

I am not sure if VB.NET understands the "\n" or you need to do string concatenation like "*idn?" + Environment.NewLine

[mikla90]

Hey everyone. Sorry, I know it's been a long time. Unfortunetly, that's how my job is done.

So, the code is now as follows:

Sub idn()
    Dim ioMgr As VisaComLib.ResourceManager
    Dim idn As String
    Dim instrument As VisaComLib.FormattedIO488
    Set ioMgr = New VisaComLib.ResourceManager
    Set instrument = New VisaComLib.FormattedIO488
    ' use instrument specific address for Open() parameter – i.e. GPIB0::22
    Set instrument.IO = ioMgr.Open("TCPIP0::192.168.1.6::5025::SOCKET")
    instrument.WriteString ("*RST")
    instrument.WriteString ("CONFigure:RESistance")
    instrument.WriteString ("SYSTem:REMote")
    instrument.WriteString ("*IDN?")
    
    idn = instrument.ReadString()
    ActiveSheet.Cells(1, 1) = idn
    
End Sub

And everything works fine untill idn=instrument.ReadString()

After that, I get the attached error. The second line is "Automation error".

The program is written in VBA in Excel 2007.

Can someone help me (again)?