How is Prologix GPIB-USB controller different from other vendors' products?

• While Prologix GPIB-USB controller provides many of the same features as GPIB-USB controllers from other vendors, it is much easier to use. Prologix GPIB-USB controller provides a virtual serial interface to communicate with instruments, while handling all GPIB protocol details for you. As a result, you can communicate easily with instruments using any terminal program instead of having to write custom programs using the vendor supplied library. Please see the Manual for a complete list of features.

Is Prologix GPIB-USB controller compatible with National Instruments LabVIEW, Agilent VEE, and other test frameworks?

• Yes. Prologix GPIB-USB controller provides a virtual serial interface to communicate with instruments, while handling all GPIB protocol details for you. Any test framework, or programming environment, that provides access to serial ports is compatible with Prologix GPIB-USB controller. For example, you may use NI LabVIEW Serial VIs or NI VISA VIs. Also, FTDI has sample LabVIEW VIs for communicating with the controller using D2XX drivers.

Will my custom LabVIEW or VEE programs work unmodified with Prologix GPIB-USB controller?

• Probably not. Prologix GPIB-USB controller provides a virtual serial interface to communicate with instruments, while handling all GPIB protocol details for you. Programs that expect a different interface (such as NI 488.2 interface) have to be modified to use the serial interface to be compatible with Prologix GPIB-USB controller.

How do I use Prologix GPIB-USB controller with LabVIEW?

• Prologix GPIB-USB controller provides a virtual serial interface to communicate with instruments. Therefore you may use LabVIEW Serial VIs or NI VISA VIs to talk to the Prologix controller and instruments.  Please see the LabVIEW sample program in the Resources section and link to Matthias Schroeter web page on using Prologix controller with LabVIEW on Linux.
  

How do I use Prologix GPIB-USB controller with MATLAB, or using C++, C#, or Visual Basic?

• Please see sample programs in the Resources section.

Is Prologix GPIB-USB controller a drop-in replacement for controllers from other vendors?

• No. Prologix GPIB-USB controller provides a virtual serial interface to communicate with instruments, while handling all GPIB protocol details for you. Programs that expect a different interface (such as NI 488.2 interface) have to be modified to use the serial interface to be compatible with Prologix GPIB-USB controller.

Can Prologix GPIB-USB controller control multiple instruments?

• Yes. You specify the GPIB address of the instrument to control using the "++addr" command. All subsequent instrument commands are sent to the specified address. When you want to control a different instrument, issue another "++addr" command with the new address.

How do I download screen plots from instruments?

• There are two ways of downloading screen plots — device initiated plots and host requested plots:

Device Initiated Plot

1. Set the instrument to TALK ONLY mode
2. Set Prologix GPIB-USB controller to DEVICE Mode (++mode 0)
3. Specify the address where the instrument expects the plotter to be (++addr <GPIB address>)
   
4. Connect the controller to the instrument and to the USB port on the PC
5. Open the virtual COM port using a terminal program like HyperTerminal, or using plotter software
6. Initiate screen plot download from device front panel

Host Requested Plot

1. Set the instrument to TALK/LISTEN (or ADDRESSABLE) mode
2. Set Prologix GPIB-USB controller to CONTROLLER Mode (++mode 1)
3. Specify the GPIB address of the instrument (++addr <GPIB address>)
4. Connect the controller to the instrument and to the USB port on the PC
5. Open the virtual COM port using a terminal program like Windows HyperTerminal, or plotter software
6. Using the terminal program, or plotter software, issue the instrument command to download screen plot (e.g. PLOT;)
   

How do I print screen plots from instruments?

• 7470.exe — an excellent open source application.
• PrintCapture — a full-featured commercial application. 30-day free trial version available.
• Plottergeist — another full-featured commercial application.

Are drivers available for my OS?

• Drivers are available for the following OS from FTDI website:

• Windows Vista x64
• Windows Vista
  
• Windows XP x64
• Windows XP
• Windows Server 2003
• Windows 2000
• Windows ME
• Windows 98
• Linux
• Mac OS X
• Mac OS 9
• Mac OS 8
• Windows CE.NET (Version 4.2 and greater)

How do I install drivers?

• Please refer to FTDI installation guides.

What accessories are needed to use Prologix GPIB-USB controller?

• At a minimum you need an USB A-B cable, with an USB-A connector at one end, and an USB-B connector at the other end. You may also need a GPIB cable.

Do I need a power supply?

• No, Prologix GPIB-USB controller is powered from the USB bus.

Do I need a GPIB cable?

• You may plug the Prologix GPIB-USB controller directly onto the GPIB connector on the instrument. The controller has a male GPIB connector and most instruments have a female GPIB connector. However, if it is not convenient to do so, you may use a GPIB cable.

How do I configure my Prologix GPIB-USB controller?

There are two easy ways to configure your Prologix GPIB-USB controller:

• Use the excellent open source PROLOGIX.EXE utility written by John Miles.
• Use any terminal program such as HyperTerminal or Tera Term Pro and enter commands manually. For example, to enable CONTROLLER mode enter ++mode 1
  

How do I use HyperTerminal with Prologix GPIB-USB controller?

Connect USB cable. Start HyperTerminal.

In "File" | "Properties" dialog, select the virtual COM port created by USB driver.

Click "OK", then select "Settings" tab and click "ASCII setup...". In the dialog, check "Send line ends with line feeds" and "Echo typed characters locally". Click "OK" twice.

You are now ready to communicate with the controller. Enter ++ver command in the HyperTerminal window to verify communication with the controller.

How do I use Tera Term Pro with Prologix GPIB-USB controller?

Connect USB cable. Start Tera Term Pro.

In "Setup" | "Serial Port..." dialog, set values as follows:

• Port: Select virtual COM port created by USB driver

Click OK. In the "Setup" | "Terminal" dialog, set "Transmit" to "CR+LF", and check "Local echo". Click OK.

You are now ready to communicate with the controller. Enter ++ver command in the Tera Term Pro window to verify communication with the controller.

How do I use 7470.exe with Prologix GPIB-USB controller?

• Please see 7470.exe User Guide.

How do I use PrintCapture with Prologix GPIB-USB controller?

Please see application note in the Resources section. Also see PrintCapture website for more details.

How do I use Plottergeist with Prologix GPIB-USB controller?

Configure the controller as a DEVICE. Connect USB cable.

Start Plottergeist. Open "Configuration" | "GPIB/RS-232..." dialog. Select "Connect using Serial Port", and click "Setup". Set values as follows:

• Port: Select virtual COM port created by USB driver

Click OK twice. Click the "On Line" button on the tool bar. Plottergeist is now ready to receive data.

Which commands do I use to control my instrument?

• Refer to the programming manual of your instrument for commands accepted by your instrument.

How do I create programs to control instruments, and acquire data, using Prologix GPIB-USB controller?

Any programming language and environment that provides access to virtual serial ports can be used to develop programs to control instruments using the Prologix GPIB-USB controller.

Also, checkout Ulrich Bangert's EZGPIB, an easy to use data acquisition tool for use with Prologix GPIB-USB controller.

Are code samples available?

• Yes. See here.

Why am I not getting any response from instruments?

• This could be due to any of the following reasons:

• Serial port was not configured correctly
• Instrument address was not set correctly in the GPIB-USB controller
• Instrument was not configured for output
• The command was not recognized by the instrument

Why is the instrument reporting "QUERY UNTERMINATED" or "-420" error when using Prologix GPIB-USB controller?

After sending any command to an instrument, Prologix GPIB-USB controller will address it to talk to read the instrument's response. If the command does not generate a response (often called non-query commands), some instruments generate the above error when addressed to talk. In effect the instrument is saying, you have asked me to talk when I have nothing to say. The error is often benign and may be ignored.

However, if you want to avoid the error you have two options:

Use the ++auto 0 command to turn off the read-after-write feature before issuing a non-query command. Later use the ++auto 1 command to turn the feature on to read instrument response when issuing query commands. For example:

Or, use the ++read command to read the instrument response. For example:

What if I have a question that is not answered here?

• Please send email with your question to support@prologix.biz. Describe in detail your problem, your setup, and any troubleshooting you have done.

Where is the user manual?

• User Manual