Edit USB/GPIB Interfaces

To edit properties of a USB/GPIB Interface Converter (Keysight 82357) that is connected to your PC:

In Connection Expert, select the USB/GPIB interface from the list of instruments and interfaces that can be edited. These are specified in the list by type and VISA interface ID (for example, USB/GPIB interface GPIB0).
Then click .
Modify the interface properties (described in detail below) as needed.
Click OK.

Notes:

Because USB/GPIB interface converters permit GPIB instruments to be connected to the PC (via the PC's USB port), they are treated as GPIB interfaces by VISA. Instruments connected via USB/GPIB interface have GPIB addresses and GPIB-style properties.
You can use multiple USB/GPIB interface converters on the same PC.
If you connected a USB/GPIB interface converter before you installed the Keysight IO Libraries Suite, you may need to disconnect the USB/GPIB interface converter from the computer and then re-connect it to complete the hardware installation.

To change the VISA implementation used on this interface, see VISA Conflict Manager.

Specify Connection Addresses

Connection Expert manages the default numbering used with the VISA interface ID, SICL interface ID, and logical unit properties. When configuring one of these properties, Connection Expert uses the next available integer value. For example, if the VISA interface ID GPIB0 is already in use on another interface, the default value for this interface becomes GPIB1.

Conflicts may occur between board numbers of different vendors' GPIB interfaces, particularly where these board numbers are set using different configuration tools (such as Keysight Connection Expert for Keysight interfaces and NI-MAX for National Instruments interfaces). Connection Expert scans for conflicts when new interfaces are detected, and renumbers Keysight interfaces if necessary.

To change another vendor's board numbers, you must use that vendor's configuration utilities (for example, NI MAX).

VISA Interface ID

A name that Connection Expert and VISA use to uniquely identify this interface. The VISA interface ID for a USB/GPIB interface is of the form GPIBn, where n is an integer. The VISA interface ID is part of the addressing string used to open a VISA programming session to a GPIB instrument.

If you have GPIB interfaces from different vendors installed in your system, you may see conflicts if the same VISA interface ID is assigned (by different vendors' configuration tools) to more than one interface. See Board Number Conflict for details.

Note that the board number (used in Keysight 488 function calls) is the numeric part of the VISA Interface ID. For example, if the VISA interface ID of your interface is GPIB1, its board number is 1.

GPIB Address

The address of this interface on the GPIB bus. The GPIB address can be any integer from 0 to 30. It is usually set to 21 if the GPIB interface is a system controller, or 20 if not a system controller.

An 82357 USB/GPIB interface converter must be the system controller; it does not support a non-controller mode. This means it controls talkers and listeners on the GPIB bus.

SICL Interface ID

A name that SICL uses to uniquely identify this GPIB interface. The default SICL interface ID is gpibn, where n is an integer. If you are not using the default SICL interface ID, enter a unique string of alphanumeric characters (it can also include the _ and - characters). The SICL interface ID can be a maximum of 31 characters long and must start with a letter. Remember this value and the logical unit number in order to address the GPIB interface properly in your SICL applications.

Logical Unit

An integer that can be used in place of the SICL interface ID in Keysight VEE and SICL applications. The logical unit is not used by VISA.

Auto-Discover Options

Auto-Discover Instruments Connected to This Interface

When the Auto-Discover check box is selected, the interface will find new instruments whenever it is scanned. When the check box is cleared, the interface does not discovery new instruments. The interface is scanned on startup of the PC, whenever you click Rescan All in Instruments view, and periodically in the background if Auto-Scan is enabled. (Auto-scan is not available on all interface types.)

Why would I clear the Auto-Discover check box?

Here are some situations when you would disable auto-discover:

Performance-sensitive situations. When the auto-discover check box is cleared:
The VISA viFindRsrc function will find only instruments that have been added manually.
VISA programs can still access an instrument if the instrument's VISA address is provided to the viOpen call.
There is not a noticeable difference in the speed of Connection Expert.

Situations in which you do not want to disturb the state of the GPIB bus. Auto-discovery causes bus addressing and handshaking to occur when it is enabled.

How is Auto-Discover different from Auto-Identify?

Auto-discovery is a property of interfaces. For each interface, you may select whether the Keysight Instrument Discovery Service should automatically scan the interface during its discovery process. The scan updates Connection Expert with the current interface and instrument configuration.

Auto-identification is a property of individual instruments. For manually-added GPIB instruments, you may select whether the Keysight Instrument Discovery Service should automatically send an identification query (*IDN?) to the instrument.

See Instrument Discovery and Identification on Specific Interface Types for more information on auto-discovery and auto-identification.

Auto-discovery defaults on for USB/GPIB interfaces.

Auto-Scan Options

By default, auto-scan is on but will be disabled automatically if problems are detected. You can choose to specify that auto-scan is always on or always off for this interface.

If Auto-Discover is turned off (cleared), then the Auto-Scan setting has no effect and is disabled (grayed).

Do Not Auto-Scan For Instruments On This Interface

If you select this option, auto-scan is turned off. New instruments will be discovered, and disconnected instruments removed, only on PC startup and when you click Rescan All .

Always Auto-Scan For Instruments On This Interface

If you select this option, the Discovery Service will scan this interface for new instruments and disconnected instruments periodically.

Auto-Scan Unless a Problem Is Detected

This is the default setting. Auto-scan is enabled unless the Discovery Service detects an instrument or condition that may cause problems on auto-scan. For example, certain instruments go in remote mode when scanned, so if one of those instruments is detected, auto-scan is disabled on this interface.

If you select Auto-Scan Unless a Problem Is Detected, you will see a message indicating the current state of auto-scan (enabled or disabled). The message may also indicate the reason if auto-scan is disabled. If auto-scan is disabled, you can still look for new or disconnected instruments by clicking Rescan All .

The IO Libraries Suite auto-scan feature can cause certain instruments on GPIB interfaces to go into remote mode every 15 seconds. When the Discovery Service detects an affected instrument model, it automatically turns off auto-scan for the affected GPIB interface. For detailed information on this issue, see Instrument Discovery and Identification on Specific Interface Types.

In addition, some older instruments do not respond correctly to the SCPI identification query, *IDN? These instruments may experience problems when queried by the IO Libraries Suite. After two failures, IO Libraries Suite will stop sending *IDN? to that instrument until the next reboot or reconnect. You can prevent *IDN? from ever being sent to an instrument by manually adding the instrument and turning off its auto-identification property.

Keysight 488 Properties

Click the down arrow to expand the properties related to the Keysight 488 library.

Click here for detailed information on the Keysight 488 properties.

The properties described below are of interest if you are programming with the Keysight 488 library, or using applications developed with that library. Most of these properties can be modified on any GPIB interface except for an NI-488.2 interface. (Use National Instruments configuration tools to modify properties on an NI-488.2 interface.)

Note that the board number (used in Keysight 488 function calls) is the numeric part of the VISA Interface ID. For example, if the VISA interface ID of your interface is GPIB1, its board number is 1.

If the Keysight 488 library is disabled, you will see this message just below the Keysight 488 Properties label:

You must check the box to enable Keysight 488 if you wish to use NI-488.2–compatible programs with Keysight interfaces. See the Keysight 488 Help for more information on enabling Keysight 488. Note that this setting also enables Agilent and Hewlett Packard GPIB cards.

Termination Settings

These five settings control the method of terminating Keysight 488 data transfers. For more information, see the Keysight 488 Help.

EOS Character: The ASCII value of the end-of-string (EOS) termination character. Note that use of a termination character (EOS mode) generally causes a degradation of performance by forcing a check of each character read against the defined EOS character.

Set EOI with the Last Character: Assert the EOI line before sending the last byte of data. This is the most commonly used method of terminating data transfers.

Set EOI with the EOS Character: Assert the EOI line along with transmission of the EOS character.

Terminate Read on the EOS Character: Terminate read operations when the EOS character is received.

8-bit EOS Compare (Read-Only): Some GPIB interfaces support selection of either 7-bit or 8-bit comparison of the EOS character. However, Keysight interfaces always employ 8-bit comparison, so this property is read-only for all Keysight interfaces.

Common Settings

I/O Timeout: The timeout period of the interface and of devices on the interface. The menu provides integer timeout codes, as used by ibtmo. in addition to the actual timeout: for example, the menu item 6 (3 msec) specifies a timeout of three milliseconds, which corresponds to ibtmo timeout code 6.

Parallel Poll Duration: The duration of a parallel poll. The default duration is two microseconds (timeout code 0). The menu provides integer duration codes, as used by ibconfig, in addition to the actual timeout: for example, the menu item 6 (3 msec) specifies a timeout of three milliseconds, which corresponds to ibconfig duration code 6. The ibconfig duration codes are the same as the ibtmo timeout codes.

Bus Timing: The timing of the GPIB Source Handshake, which allows a device to send command or data bytes over the GPIB. See the Keysight 488 Help for more information on handshaking.

Automatic Serial Poll: Enables automatic serial polling, which causes the active controller to serial poll all devices on the GPIB interface each time the SRQ line is asserted. See the Keysight 488 Help for more information.

Assert REN When System Controller: If checked, causes the REN line to be asserted when this interface is opened (by a call to ibfind or to any Keysight 488 extended function that causes a session to be opened on this interface).

Saving the Configuration

The OK button is enabled if you have made changes to the information in this view. When you have finished entering the information, click OK to save the configuration or Cancel to revert to the previous saved values.