Open

Opens a session to the device and returns a session identifier that you can use to call any other operations of that device.

1378

Inputs/Outputs

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open timeout

The maximum time period, in milliseconds, that Open waits before returning an error. This parameter does not set the I/O timeout.

To specify the timeout used for future operations on the VISA session, use the Timeout property in VISA Properties by selecting General Settings » Timeout Value.

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resource name

The resource to be used.

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Default value: No error

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duplicate session

A Boolean that specifies whether to open an additional session to a resource even if another session is already open.

True Opens a new session to the resource even if another session is already open.
False Connects to the resource using an existing session if one exists. Otherwise, opens a new session.
A VISA session is a unique logical identifier used by VISA to communicate with a resource. The VISA session is maintained by the resource name parameter and is not seen by the user.

Default value: False

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access mode

Setting that specifies how to access the device.

VISA Defaults 0 Opens a session without using an exclusive lock or loading configuration information.
Exclusive Lock 1 Acquires an exclusive lock immediately upon opening a session. If a lock cannot be acquired, the session is closed and an error is returned.
Load Configured Settings 4 Configures attributes to values specified by an external configuration utility.
Load Configured Settings with Exclusive Lock 5 Acquires an exclusive lock immediately upon opening a session and configures attributes to values specified by an external configuration utility.

Default value: VISA Defaults

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session out

The resource to which a VISA session is opened.

This output also includes the class for the session, which matches that of resource name.

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error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Opening Multiple VISA Sessions

If you open a significant number of VISA sessions without closing them, you decrease the available memory resources. Close the session with Close.

Note This function recognizes all resource strings returned by Find Resource. However, Find Resource does not necessarily return all strings that you can pass to this function.