GPIB-USB Controller 3.x Manual
- Features
- Installation
- Device Mode
- Controller Mode · (Example)
- Commands
- Sample Programs
- DIP Switch Settings
- Technical Specifications
- Frequently Asked Questions
Turn any computer with an USB port into a GPIB controller with this low cost GPIB-USB controller! Use this controller to control, and to download screen plots and data from, Oscilloscopes, Logic Analyzers, Spectrum Analyzers and other GPIB enabled instruments.
Features
- Drivers for Windows 98/ME/2000/XP, Mac OS-8/9/X, Linux
- Device and Controller modes
- Support for multiple devices
- Driver provides virtual COM port to send and receive data
- Powered by USB; no power supply needed
- No GPIB cable needed; controller plugs on to instrument
- USB 1.1 and USB 2.0 compatible
- Standard USB (B) and IEEE 488 (Male) connectors
Installation
To install the controller do the following:
- Download drivers for FT232BM from www.ftdichip.com/Drivers/VCP.htm
- Connect controller to computer using an USB (A-B) cable
- Install drivers according to www.ftdichip.com/Documents/InstallGuides.htm
- Plug controller directly, or using a GPIB cable, on to the GPIB connector of the instrument
- Configure the virtual COM port to
115,200 baud, 8-bit data, no parity, 1 stop bit and hardware (RTS/CTS) flow control - Open the port using any terminal program (e.g. HyperTerminal, Tera Term Pro)
- Configure the terminal program to
always send Line Feed with Carriage Return - Send commands or receive data
To render screen plots graphically we recommend any of the following software:
- 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.
Device Mode
In Device mode, the GPIB-USB Controller acts as another device on the GPIB bus. In this mode, the GPIB-USB Controller can act as a GPIB Talker or GPIB Listener only. Since the GPIB-USB Controller is not a System Controller in Device mode, it expects to receive GPIB commands from the Controller-In-Charge (CIC). On power up in Device mode the GPIB-USB Controller is configured as a GPIB Listener. All data received by the GPIB-USB Controller over the GPIB port is passed along to the USB port. When you are expecting to receive data from the USB device, address the GPIB-USB Controller to talk, and all data received over the USB port is passed along to the GPIB port. When you are ready to send data to the USB device again, address the GPIB-USB Controller to listen.
Note: Use Device mode to download screen plots from instruments.
Controller Mode
In Controller mode, the GPIB-USB Controller acts as a System Controller. On power up in Controller mode the GPIB-USB Controller asserts IFC to become Controller-In-Charge (CIC). After the GPIB-USB Controller becomes CIC, it addresses the GPIB instrument to talk. The GPIB-USB Controller always asserts REN when addressing devices. All data received over the GPIB port is passed along to the USB port. When GPIB-USB Controller receives any character over the USB port it addresses the GPIB instrument to listen and passes along the received data. It remains in this mode until the Line Feed character (0x0A) is received over the USB port, at which time the GPIB-USB Controller re-addresses the GPIB instrument to talk.
Note: Use Controller mode to send commands to instruments. Terminate commands with a Line Feed character (0x0A) to notify GPIB-USB Controller to address the GPIB instrument to talk after sending the command. This is required to receive any output from the instrument.
Example
The GPIB-USB controller was installed and configured as described earlier. It was plugged onto the GPIB port of a HP 54201A Digital Storage Oscilloscope. User opened the virtual COM port with HyperTerminal and performed the following dialogue:
id? |
? | Command typed by user |
"HP54201A" |
? | Response from DSO |
ser? |
? | Command typed by user |
"2738A02659" |
? | Response from DSO |
plot; |
? | Command typed by user |
lbdf;sc0,575,0,367... |
? | Response from DSO |
As you can see from the above example, the GPIB-USB controller makes communicating with any GPIB instrument easy and intuitive.
Commands
When the GPIB-USB controller is in Controller mode it understands the following commands send over virtual COM port.
| Command | Description |
|---|---|
++addr 0-31 |
Tell controller which device to address [Default set by DIP switch] |
++addr |
Query currently configured device address |
++clr |
Issue device clear |
++eoi 0|1 |
Enable (1) or disable (0) EOI with last byte. Default is 0. |
++eoi |
Query current EOI setting |
++eos 0|1|2|3 |
EOS terminator — 0:CR+LF, 1:CR, 2:LF, 3:None. Default is 0. |
++eos |
Query current EOS setting |
++ifc |
Issue interface clear |
++loc |
Return device to local mode |
++spoll |
Read status byte by serial polling the device |
++srq |
Query status of SRQ line. 0: Not asserted, 1:Asserted |
++trg |
Issue device trigger |
++ver |
Query GPIB-USB controller version |
++help |
Print help about commands |
You are most likely to use the if more than one instrument is connected to the GPIB-USB controller. In such cases you can use the ++addr command to address each instrument in turn, before talking to it. For example:
++addr 7 |
? | Tell controller to address instrument at GPIB address 7 |
id? |
? | Issue command |
"HP54201A" |
? | Response from instrument at address 7 |
++addr 8 |
? | Tell controller to address instrument at GPIB address 8 |
*idn? |
? | Issue command |
"HP1651B" |
? | Response from instrument at address 8 |
Sample Programs
Following sample programs demonstrate how to programmatically send and receive data from the GPIB-USB controller. They were developed using Microsoft Visual Studio Express Edition on Windows XP SP2 and tested using FTDI driver version 2.00.00.
- C/C++ sample
- C# sample (Requires Microsoft .NET 2.0)
- Visual Basic.NET sample (Requires Microsoft .NET 2.0)
DIP Switch Settings
Disconnect all cables and power down before changing DIP switch settings.
| Mode | DIP Switch #6 |
|---|---|
| GPIB-USB Controller operates in Device Mode | OFF |
| GPIB-USB Controller operates in Controller Mode | ON |
| GPIB Address | DIP Switch | ||||
|---|---|---|---|---|---|
| #1 | #2 | #3 | #4 | #5 | |
| 0 | OFF | OFF | OFF | OFF | OFF |
| 1 | ON | OFF | OFF | OFF | OFF |
| 2 | OFF | ON | OFF | OFF | OFF |
| 3 | ON | ON | OFF | OFF | OFF |
| 4 | OFF | OFF | ON | OFF | OFF |
| 5 | ON | OFF | ON | OFF | OFF |
| 6 | OFF | ON | ON | OFF | OFF |
| 7 | ON | ON | ON | OFF | OFF |
| 8 | OFF | OFF | OFF | ON | OFF |
| 9 | ON | OFF | OFF | ON | OFF |
| 10 | OFF | ON | OFF | ON | OFF |
| 11 | ON | ON | OFF | ON | OFF |
| 12 | OFF | OFF | ON | ON | OFF |
| 13 | ON | OFF | ON | ON | OFF |
| 14 | OFF | ON | ON | ON | OFF |
| 15 | ON | ON | ON | ON | OFF |
| 16 | OFF | OFF | OFF | OFF | ON |
| 17 | ON | OFF | OFF | OFF | ON |
| 18 | OFF | ON | OFF | OFF | ON |
| 19 | ON | ON | OFF | OFF | ON |
| 20 | OFF | OFF | ON | OFF | ON |
| 21 | ON | OFF | ON | OFF | ON |
| 22 | OFF | ON | ON | OFF | ON |
| 23 | ON | ON | ON | OFF | ON |
| 24 | OFF | OFF | OFF | ON | ON |
| 25 | ON | OFF | OFF | ON | ON |
| 26 | OFF | ON | OFF | ON | ON |
| 27 | ON | ON | OFF | ON | ON |
| 28 | OFF | OFF | ON | ON | ON |
| 29 | ON | OFF | ON | ON | ON |
| 30 | OFF | ON | ON | ON | ON |
| 31 | ON | ON | ON | ON | ON |
Technical Specifications
| Supported OS | Windows 98/ME/2000/XP, Mac OS 8/9/X, Linux |
|---|---|
| Supported Standards | USB 1.1, USB 2.0, IEEE 488.1 |
| Unsupported GPIB modes | Parallel Poll, Pass Control |
| Power | USB bus powered device, +5V, 100mA (max) |
| Support for USB hubs | Self-powered and bus-powered hubs |
| Data transfer rate | 115,200 baud |
| Data format | 8-bit data, no parity, 1 stop bit, hardware flow control |
| Configuration | DIP switch for GPIB address and Device mode |
| Indicators | Power, Device mode, Data |
| Dimensions | 2.8 inch (L) x 2.5 inch (W) x 1.0 inch (H) |
Frequently Asked Questions
See FAQ.
