Raptor:CAN Send Message

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Raptor™ CAN Send Message

Description

Each CAN tx message block not set to transmit periodically has a transmit queue. This queue is used to store messages if the transmit block is executed faster than the messages can be transmitted on the CAN bus. This will typically happen if the tx raw block is located in a for or while loop. If the queue is full when the block executes the oldest tx message will be overwritten.

The payload mask and value can be used to specify a particular value for certain bits in the message. All bits in the message with a 1 in the payload mask will be initialized to the value in the payload mask value. The contents of the message will then be bitwise or'd together.

A signal's initial value (aka the start value) can be defined in the DBC using signal attributes named 'GenSigStartValue'.

The ID input allows for calibration of CAN message ID after building the software. It is important to note that the transmitted message ID will be: [(ID && Mask) || (ID Port && !(Mask))] where 'ID' is the parameter, and 'ID Port' is the input. This means that at runtime you can only alter the parts of the ID that are not 1 in the mask.

If the Tx Period is set to 0 (or a negative number) for asynchronously transmit the message, you should consider how frequently the containing subsystem is executing. It is easy to send more frequently than you may expect or need. For example, an asynchronously transmitted message in a 5ms task will transmit 200 times per second, which would be 10% of the total bus load on a 250K CAN bus.

250K CAN Bus - handles about 2000 msg/sec

500K CAN Bus - handles about 4000 msg/sec

1000K CAN Bus - handles about 8000 msg/sec

Inputs

Input	Type	Description
ID	uint32	The ID used in the receive message filter. This is automatically set from the dbc file. Shown/hidden by the "Show ID Port" checkbox.
IsDataValid	boolean	Whether the data received at the signal ports is valid. If true, sends the signal values received; if false, sends the signal start values defined in the DBC. Signal attribute 'GenSigStartValue' is used to define a start value in the DBC; if the attribute is not defined for that signal, the value will be 0. Shown/hidden by the "Use Start Vals" checkbox.
Signals	uint32	Any signals from the .dbc that are enabled will appear as inputs on this block.

Parameters

Parameter	Type	Description
.dbc File		The dbc file being used. Click the Load button to select a new dbc file.
Message List		A list of messages defined in the dbc file, click on a message name to select a new message.
Side/DLC	Number	The length of the CAN Message in bytes.
CAN Bus	String	The CAN bus to transmit the message on.
Signal Order	Select	The option to how the signals are sorted within the GUI.
Edit ID	Checkbox	Allows the Message ID to be edited.
Message ID	Number	The ID used in the transmit message filter. This is automatically set from the dbc file.
ID Mask	Number	The mask used in the transmit message filter.
Queue	Number	Specifies the size of the transmit queue.
Payload Value	Vector	The value used with the payload filter for messages. This will be set automatically for messages with a mode signal.
Payload Mask	Vector	The mask used with the payload filter. This value will be set automatically for messages with a mode signal.
Tx Interval	Number	Specifies the period to transmit the CAN message. Set this value to 0 or a negative number to transmit the message each time this block executes (asynchronously).
Fill unused bits with '1'	Checkbox	Any unused bits in the message will be filled with ones.
Use Pretransmit Simulink Function Callback	checkbox	Whether to use a Simulink Function callback as a pretransmit hook. The Simulink Function takes in the raw CAN data to be transmitted & allows the data to be checked and/or manipulated before being sent out on the bus. Messages longer than 8 bytes are not supported on single-transmit CAN blocks; please use CAN FD or a transport protocol (UDS/J1939) instead.
Simulink Function Name	String	Name of the Simulink Function to call when the CAN pretransmit hook is triggered.
Create	button	Create a Simulink Function to call when this CAN pretransmit hook is triggered. Must first provide a valid function name.
Update	button	Update the signature of an existing Simulink Function to have 2 inputs and 2 outputs.
Enable	Checkbox	Enable or disable signals within a message.
Scaled	Checkbox	Enable or disable scaling of the signal.
Show ID Port	Checkbox	Makes the ID port available.
Label Port Signals	Checkbox	Enable this to automatically name the wires on the output ports with the names of the signals.
Use Start Vals	Checkbox	Enable this to specify signal start values from the DBC instead of using the default (all zeroes). This also adds one extra input port, "IsDataValid". When the value at that port is True, the signal values are taken from the input ports as usual; when the value at the port is False, the Tx block will send out the default values defined in the DBC. Signal attribute 'GenSigStartValue' is used to define a start value in the DBC; if the attribute is not defined for that signal, the value will be 0.