Operation Modes

NI Switches Help

Edition Date: April 2015

Part Number: 375472H-01

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NI-SWITCH offers two operation modes for programming National Instruments switches: immediate operations and scanning. During scanning, each operation in the scan list occurs after an event. Immediate operations occur instantly or as fast as the relay or relays can actuate.

Immediate Operations

During immediate operations, relays are actuated after each VI or function call rather than waiting for a trigger.


Scanning is typically used when timing of connections must be synchronized with an event from another device, such as a measurement device (hardware-timed scanning), or must be timed by software (software-timed scanning).

Connection operations are entered in a scan list that is downloaded to the memory of the switch module. The first entry in the scan list is executed when the scan is initiated. The trigger settings determine how the switch advances through subsequent entries in the list. The scan list can be executed once or repeatedly.

There are three trigger schemes for scanning: software trigger scanning for software-timed scanning, synchronous scanning for hardware-timed scanning, and handshaking for hardware-timed scanning.

Note Note  Some devices may not support scanning. Refer to your device book for more information about supported features.


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