Using a Remote Interface for LAN Access

Using a Remote Interface for LAN Access

Agilent VISA provides three types of VISA LAN Client interfaces, implemented in Agilent IO Libraries Suite as remote interfaces:

• Remote serial interface (ASRL VISA LAN Client)
• Remote GPIB interface (GPIB VISA LAN Client)
• Remote USB interface (USB VISA LAN Client)

Remote interfaces are configured using Connection Expert; they provide virtual GPIB, serial, or USB interfaces. They make it possible to remotely access a LAN-connected device as if it were connected to a local interface. If, for example, the GPIB2  interface is configured as a remote GPIB interface, a program controlling the devices GPIB2::5::INSTR and GPIB2::7::INSTR would not be aware of the fact that these devices are actually connected via LAN and not to a GPIB interface connected to the local machine.

Note: See the Agilent IO Libraries Suite Help for specific information on configuring remote interfaces.

Remote Serial Interface (ASRL VISA LAN Client)

A remote serial interface can use only the SICL-LAN protocol. A remote serial interface can be configured to use the serial port on the Agilent E5810A LAN/GPIB gateway or the serial ports on a PC running the Remote IO Server software.

Remote GPIB Interface (GPIB VISA LAN Client)

A remote GPIB interface can use both the VXI-11 and SICL-LAN protocols. Typical uses for remote GPIB interfaces are with LAN/GPIB gateways (for example, Agilent E5810A), PCs with GPIB interfaces that are running a LAN server, and VXI-11.2 LAN-based instruments.

A remote GPIB interface can only be used to communicate with VXI-11.2 (GPIB Emulation) devices. This is because the VISA GPIB interface type requires a primary and (optionally) a secondary address when communicating with a device. VXI-11.3 devices do not support the concept of a primary address, so they cannot be accessed with a remote GPIB interface.

Remote USB Interface (USB VISA LAN Client)

A remote USB interface can use only the SICL-LAN protocol. It can communicate with USB devices attached to a remote PC running the Remote IO Server software.

Note that if you have defined a VISA alias for a USB device on the remote I/O server, you must either define the same (or another) alias for the remote USB device on the client PC, or use the full USB resource string. Alias definitions are not shared between the remote I/O server and the client.

Addressing a Session Using a Remote Interface

In general, the rules to address a remote session are the same as to address a local session. The only difference for a remote session is that you use the VISA interface ID (provided during I/O configuration via Connection Expert) that relates to the remote interface.

The following sample shows one way to open a device session with a GPIB device at primary address 23 on a remote PC that is running Remote IO Server software. A remote GPIB interface has been configured at GPIB2 to communicate with that machine. See Programming with VISA, for more information on addressing device sessions.

ViSession defaultRM, vi;.

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viOpenDefaultRM(&defaultRM);

viOpen(defaultRM, "GPIB2::23::INSTR", VI_NULL, VI_NULL, &vi);

.

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viClose(vi);

viClose(defaultRM);