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10.
CANopen communication protocol
The most important document to understand the communication with the keypad is the K-
Matrix. It includes a description of all available objects, how to address them and how to save
them. It is the equivalent to the object dictionary. To work with the K-Matrix please note that
some objects have a at the side. Which means that the row can be expanded and more
information is then available.
This manual includes excerpts from the K-Matrix. All functions that the keypad has to offer can
be found in the K-Matrix. All addressable objects are also defined in the corresponding EDS
(electronical data sheet) file. To interface correctly with the keypad the use of the latest EDS
is mandatory.
Composition of the CAN Identifier
The CAN-IDs are composed according to the CAN open standard which is defined in the official
CAN in Automation (CiA) Document CiA301 “CANopen application layer and communication
profile”.
The Identifier consists of 11 Bit. The first 7 Bits are the Node-ID which identifies the addressed
device. The other 4 Bits contain the function code which identifies the type of message is sent
and what it does.
The definitions of the function code can be found in the corresponding document CiA301.
Standard communication parameters
The default Node-ID of the keypad is set to 0x0B (0d11) by default. It can be modified either
by using the LSS master commands or by a specific CAN message to the corresponding object
as described in 10.4.
The default baud rate of the Keypad is set to 250kbps. It can also be changed by means of
LSS master or a specific CAN message according to 10.4.
Installation in a CAN-network
After connecting the keypad electronically to the network it signifies its status to the master by
sending a network management message according to CiA301. It is sent with the function code
0x700 + node ID. It contains 1 data byte with the content 0x00. After that the keyboard signals
its current status by means of a heartbeat. By default it will send a message with the ID
0x700+node ID with 1 databyte containing 0x7F which signals that the keypad is in pre-
operational state. The timing of the heartbeat can be adjusted according to the CANopen
standard CiA301.
Switching in between the NMT states is defined in the official CANopen documentation CiA301.
The following is an excerpt to visualize the different states.