Default Payload

Default Payload

Data Type	Direction	Required?	Default
	Read/Write	No	Array of All 0 or 0xFF (J1939)

Property Class

XNET Frame

Short Name

DefaultPayload

Description

The frame default payload, specified as an array of bytes (U8).

The number of bytes in the array must match the XNET Frame Payload Length property.

This property's initial value is an array of all 0, except the frame is located in a CAN cluster with J1939 application protocol, which uses 0xFF by default. For the database formats NI-XNET supports, this property is not provided in the database file.

When you use this frame within an NI-XNET session, this property's use varies depending on the session mode. The following sections describe this property's behavior for each session mode.

Frame Output Single-Point and Frame Output Queued Modes

Use this property when a frame transmits prior to a call to the XNET Write VI. This can occur when you set the XNET Session Auto Start? property to false and call the XNET Start VI prior to the XNET Write VI. When Auto Start? is true (default), the first call to the XNET Write VI also starts frame transmit, so this property is not used.

The following frame configurations potentially can transmit prior to a call to the XNET Write VI:

• CAN:Timing Type of Cyclic Data
• CAN:Timing Type of Cyclic Remote (for example, a remote frame received prior to a call to the XNET Write VI)
• CAN:Timing Type of Event Remote (for example, a remote frame received prior to a call to the XNET Write VI)
• FlexRay:Timing Type of Cyclic
• LIN frame in a schedule entry of type unconditional

The following frame configurations cannot transmit prior to a call to the XNET Write VI, so this property is not used:

• CAN:Timing Type of Event Data
• FlexRay:Timing Type of Event
• LIN frame in a schedule entry of type sporadic or event triggered

Frame Output Stream Mode

This property is not used. Transmit is limited to frames provided to the XNET Write VI.

Signal Output Single-Point, Signal Output Waveform, and Signal Output XY Modes

Use this property when a frame transmits prior to a call to the XNET Write VI. Refer to Frame Output Single-Point and Frame Output Queued Modes for a list of applicable frame configurations.

This property is used as the initial payload, then each XNET Signal Default Value is mapped into that payload, and the result is used for the frame transmit.

Frame Input Stream and Frame Input Queued Modes

This property is not used. These modes do not return data prior to receiving frames.

Frame Input Single-Point Mode

This property is used for frames the XNET Read VI returns prior to receiving the first frame.

Signal Input Single-Point, Signal Input Waveform, and Signal Input XY Modes

This property is not used. Each XNET Signal Default Value is used when the XNET Read VI is called prior to receiving the first frame.