DCAN station objects

A station object describes a virtual DCAN station (CAN connection). If more than one DCAN station is used, then a unique virtual name has to be assigned to each station object.

Each DCAN station has its own FIFO to buffer received CAN messages. The size of the FIFO buffer and the corresponding timeouts are set with station parameters. On a DCAN station, bus nodes with different designs can be grouped together and operated with different settings (Receive FIFO, Timeouts).

The user can determine the distribution in DCAN stations according to his requirements. However, note that each station requires Windows resources (RAM, path objects, threads, etc.). Therefore, the number of stations should be kept within limits.

The virtual station name and station parameters are defined in the station object's connection description. Within the connection description, individual parameters are differentiated between using parameter identifiers. These parameter identifiers always begin with the "/" character. At least one blank space needs to be between individual parameter entries.

Connection description syntax:

[/CN=<Name>] [/<Identifier1>=<ParameterValue> [/<Identifier2>=<ParameterValue> ... ]]

The following table shows all parameters which can be defined for DCAN communication in the station object's connection description.

Par.	Values	Settings	Description
/CN	Name	"DefStation"	Virtual station name Only alphanumeric characters and the "_" (underscore) character may be included in names. Names may only be up to 31 characters long. Names are also case sensitive. Example: "/CN=Main". In an earlier version, the virtual station name was defined using the /DA parameter. This parameter can continue to be used in place of the /CN parameter. However, new applications should always use the /CN parameter.
/FS	1 - 65535	100	Size of the receive buffer (FIFO) in the CAN driver The value specifies the number of CAN messages. Only CAN messages whose IDs are enabled using an assigned variable object (read object) are written to the receive buffer. The necessary buffer size is therefore arranged only according to the frequency with which enabled CAN messages can occur on the CAN bus. Example: "/FS=200"
/TR	1 - 60000	1000	Timeout for RTR read request in ms After an RTR read request, the response from the opposite station needs to be received within the set time. If this doesn't happen, then Timeout Error 14987 is reported. This parameter is only significant if used in connection with RTR read objects. Example: "/TR=100"
/TW	1 - 2000	250	Write procedure timeout in msec If the write request cannot be executed within the set time (e.g. CAN bus is occupied by CAN messages with higher priority), then the write procedure is cancelled and Timeout Error 14986 is reported. Internal write procedures (such as registering or deregistering RTR objects) can also report Error 13036. Example: "/TW=50"
/RW	1 – 10000 0=none	*)	Write request delay time in msec Along with the delay time for write requests, a defined delay time is adhered to between the most recently received CAN message and the next CAN message to be sent. Example: "/RW=0"
/CF	0, 1	0	"/CF=0": Do not empty receive buffer (FIFO) before the write procedure (default setting). "/CF=1": Empty receive buffer (FIFO) before each write procedure (deletes).

The /RW parameter can also be set with the B&R CAN device configurator. If this parameter is not specified in the connection description, then the value set in the configurator is used. If this parameter is specified in the connection description, then the corresponding configurator setting is overwritten.

Connection description example:

CD="/CN=ExtIO /FS=250 /TW=100"