how to work lab view with ORion 720Aplus pH meter

[YDURUST]

I have difficulty with labview while connecting ORION 720APlus pH meter and evaluate the data in labview.

I would very appreciate if anyone could help.

Thanks in advance.

Y Durust

[Dennis_Knutson]

Exactly what kind of difficulty are you having? You need to provide details such as interface type (serial, gpib, etc) or any errror messages you might be getting. The more details you provide, the easier it will be for someone to help.

[YDURUST]

Dear Dennis,

Thank you for reply.

I installed LabVieW on a PC with Windows Xp and connected the ORION 720A PLUS pH meter with a RS-232 cable with 9-pins.

PC did not see the pH meter but I could send an empty file to printer. But I could not send the pH data .

I would wait your response.

YD

[Dennis_Knutson]

I'm not sure I understand what you mean that the 'pc did not see the ph meter'. If you are talking about using MAX (Measurement & Automation Explorer), the only thing that should be detected in MAX is the com port that you have in the pc. If you are having problems communicating with the instrument, then I suggest that you first try using Hyperterminal. If you have problems there, it could be because of any number of problems. You could have a mismatch in the com settings. Make sure the baud rate, parity, stop bits, handshaking are set exactly like the manual from the vendor says. You also have to make sure that the serial cable is the correct type. One type of cable is what is sometimes called a null-modem cable. With this type, the tx and rx wires in the cable are swapped. This means that pin 2 on the first end is connected to pin 3 at the other. Pin 3 on the first end is connected to pin 2 at the other. Other serial cables are wired straight through. Serial instruments use both types and you have to get that information from the vendor and then check the cable with an ohmmeter if you don't know the type.

[YDURUST]

I did all the settings as given by vendor for COM port settings and and also for cable connection.

What we are doing is exactly as follows:

We are titrating an organic compound (base) with acid.And we want the mV values measured with pH meter to transfer Lab view DAQ menu. We could not manage this.

YD

[Dennis_Knutson]

What does the LabVIEW DAQ menu have to do with anything? You've been talking about a serial instrument and not an NI DAQ board.

[YDURUST]

Yes.There is serial connection with pH meter and PC.

DAQ assistant has commands  for enter data/evaluate data according the type of edg. analog or digital input/output; Counter Input/output.

[Dennis_Knutson]

You keep talking about the DAQ functions but none of those apply. Your instrument is a data acquisition device only in the broad sense of the term. But then again, a mouse or keyboard are data acquisition devices in the broad sense of the term. In the LabVIEW/NI world, DAQ refers only to special devices from NI. These are devices like their M-Series boards that plug into a pci slot of your computer or their USB devices that you connect to the pc's USB port. In order to get data from your instrument, you have to use the serial instrument functions on the Instrument I/O palette. You use a VISA Write to send a command to the instrument and then do a VISA Read to get the instrument's reply. You might want to open the LabVIEW Bookshelf and read the shipping document called 'LabVIEW Measurements Manual' to get more information on the distinction between DAQ devices and external instruments.