02.00 Start-Up
SIEMENS AG 6RX1700-0AD76 7-27
SIMOREG DC Master Operating Instructions
7.7.3 Sequence of operations for starting up CAN bus boards (CB2, CBC):
1 Switch off the power supply and insert the board or adapter with board into a module location.
Please remember to insert a board in location 2 before you use location 3.
2 The following are important communication parameters. Index 1 of each parameter is set for
the 1
st
communication board (1
st
CB) and index 2 for the 2
nd
communication board (2
nd
CB):
- U711 Basic identifier for PKW Request/PKW Response
- U712 Basic identifier for PZD Receive
- U713 Basic identifier for PZD Send
- U714 No. of PZD for PZE Send
- U715 Updating rate for PZD Send
- U716 Basic identifier for PZD Receive Broadcast
- U717 Basic identifier for PZD Receive Multicast
- U718 Basic identifier for PZD Receive Internode
- U719 Basic identifier for PKW Request Broadcast
- U720 Baud rate
- U721 Reserved for CAN profile (not currently in use, leave setting at 0)
- U722 Telegram failure time (0 = deactivated)
- P918 Bus address
- P927 Parameterization enable (need be set only if parameter values are to be altered via
the CAN bus)
- The process data of the 1
st
or 2
nd
communication board are connected by means of the
appropriate connectors and binectors (see function diagrams showing "Process data
exchange with the technology or communication board with lower slot letter" or "Process
data exchange with the communication board with higher slot letter" in Section 8).
For meaning of bits of control and status words, please see Section 8, "Control word 1",
"Control word 2", "Status word 1" and "Status word 2".
3 Turn the electronics supply voltage off and on again or set U710.001 or U710.002 to "0" to
transfer the values of parameters U711 to U721 and P918 to the supplementary board.
Note: The initialization process may interrupt the communication link to a supplementary
board which is already operational.
The CAN (Controller Area Network) fieldbus is being used increasingly for industrial applications in
spite of its limited network length (max. 40 m with a data transmission rate of 1 Mbaud).
In contrast to other busses such as PROFIBUS, there are no node addresses on the CAN bus, but
telegrams are individually identified for transmission purposes. Each data message, the so-called
COBs (Communication Objects), has its own individual identifier and contains a maximum of 8
bytes of user data. The CB2 and CBC boards use the Standard Message Format with 11-bit
identifiers. Simultaneous use by other nodes of Extended Message Format with 29-bit identifiers is
tolerated, but messages with this format are not evaluated.
Nodes on the bus determine from the identifier which telegrams apply to them. The COBs to be
sent and received by each node must be defined before data transmission commences.
The identifiers also determine bus accessing priority. Low identifiers gain faster access to the bus,
i.e. they have higher priority then high identifiers.
Errored telegrams can be reliably detected by means of a number of interactive error detection
mechanisms. A transmission is automatically repeated when errors are detected.
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