CanRecv – Receive CAN message

Block SymbolLicensing group: CANDRV

Function Description

The CanRecv block receives message via CAN bus. The message is defined by the msgId, data and length inputs and the RTR and EXT parameters.

Number of messages received in the current task period (i.e. since the previous execution) is indicated by the nDRDY output.

The data from the last received message is available at the msgId, data and length outputs. Previous messages (with respect to the nmax parameter) are available using the CanItem block(s) linked to the itemRef output.

The block must be linked with the CanDrv driver. The driver must be configured to use the simple CAN mode (i.e. the parameter $NodeMode = 256$ ).

The block’s name must be in the form <DRV>__<blkname> (see e.g. OUTQUAD or OUTOCT blocks for details about referencing data from I/O drivers). The <blkname> part of the name has no special meaning in this case and it is recommended to keep the original CanRecv.

The block supports short (11-bit) and long (29-bit) message IDs (see the EXT parameter) and RequestToReceive messages (see the RTR parameter). FD mode which allows up to 64 data bytes in a single message is not supported.

Outputs

itemRef	Secondary received packet reference	Reference
msgId	CAN message ID (COB-ID)	Long (I32)
data	Message data (8 bytes maximum, LSB first) $↓$ -9.22337E+18 $↑$ 9.22337E+18	Large (I64)
length	Message length (number of bytes of data) $↓$ 0 $↑$ 8	Long (I32)
nDRDY	Number of received messages in the last period $↑$ 255	Word (U16)
iErr	Error code	Error
age	Elapsed time since the last received message [s] $↓$ 0.0	Double (F64)

Parameters

filterId	MessageId of packets to receive by this block $↓$ 0 $↑$ 536870911	Long (I32)
filterIdMask	Mask for the filterId parameter (marks valid bits) $↓$ 0 $↑$ 536870911	Long (I32)
filterLength	Data length of packets to receive by this block (-1 allows all lengths) $↓$ -1 $↑$ 8	Long (I32)
RTR	Request To Receive flag $⊙$ on	Bool
EXT	Extended message ID (29bits) $⊙$ on	Bool
timeout	Error is indicated if no packet is received within the timeout interval [s] $↓$ 0.0	Double (F64)
nmax	Maximum number of received messages in one period $↓$ 1 $↑$ 255	Long (I32)

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