Disabling Digital Filtering

NI Switches Help

Edition Date: April 2015

Part Number: 375472H-01

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Digital filtering, enabled by default, prevents the switch module from being triggered by pulses that are less than 150 ns on PXI trigger lines 0–7. Some devices used with a switch may only be able to send triggers that are less than 150 ns. For the switch module to recognize these pulse widths, digital filtering must be disabled.

You can disable digital filtering by using the niSwitch Property Node or the niSwitch_SetAttributeViBoolean function. Complete the following steps to disable digital filtering.

Caution  When digital filtering is disabled, it is possible for the switch module to be triggered by noise on the PXI trigger lines. If the device triggering the switch is capable of sending pulses greater than 150 ns, you should not disable digital filtering.
  1. Add the niSwitch Property Node to the block diagram.
  2. Click the property node and select Module Characteristics»Digital Filter Enable.
  3. Right-click the Digital Filter Enable property and select Change to Write.
  4. Right-click the Digital Filter Enable property and create a constant.
  5. Set the constant to False.


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