Creating a LocalNode

A LocalNode is the CiA 301 implementation of a CANopen node in golang. It has it's own CANopen stack, which is run within a goroutine. When creating a local node, the library parses the EDS file and creates the relevant CANopen objects. This is different from other implementations that usually require a pre-build step that generates .c/.h file that will then be used inside of the application.

Usage

To create a CANopen node :

network := canopen.NewNetwork(nil)
network.Connect("socketcan","can0",500000)
defer network.Disconnect() // properly disconnect

// Create a node with id 0x10 using the example EDS
node := canopen.CreateLocalNode(0x10,"../testdata/base.eds")

Thats it ! The node will go automatically to NMT state OPERATIONAL if there are no errors. A callback can be added that will be called by the node's goroutine. It must be non blocking.

// Called every stack tick, i.e. ~10ms
func NodeMainCallback(node canopen.Node) {
    od := node.GetOD()
    // Get manufacturer device name
    deviceName, _ := od.Index(0x1008).GetRawData(0, 0)
    fmt.Println("My name is : ", string(deviceName))
}

node.SetMainCallback(NodeMainCallback)

Note that there are several ways of accessing data in the object dictionnary. Some standard functions are provided for direct memory access to the OD. However, all nodes come with a local sdo client for reading the internal OD. Here are some examples:

od := node.GetOD()
od.Index("UNSIGNED32 value").Uint32(0) // Get od value as a uint32, if length is incorrect, it will error

localNode := node.(*canopen.LocalNode) // Get actual type : *canopen.LocalNode
localNode.ReadUint("UNSIGNED32","") // Returns it as uint64
localNode.ReadUint("UNSIGNED8","") // Returns it as uint64 also
deviceName,_ := localNode.ReadString(0x1008, 0x0) // This corresponds to device name

See BaseNode go doc for more information on the available methods.