Siemens Simatic Operating Instructions Manual page 55

Table 4- 13
Byte.Bit
0.7
0.6
0.5
0.4 ... 0.1
0.0
1.7
1.6
1.5
1.4 ... 4.0
5-12
SIMATIC PN/CAN LINK
Operating Instructions, 03/2018, A5E39895388-AB
Structure of input data for receive proxy modules (from PN/CAN LINK to S7 controller,
13 bytes)
Meaning
Message exists
0 = No message in the receive buffer
1 = Message(s) in the receive buffer
Bit is always "1" when the transfer bit = 1 because the message stays "in the buffer" until
the transfer is "completed".
Receive filter
0 = A valid receive filter is set.
1 = No valid receive filter was set. When the receive filter bit is "0", no messages at all
are forwarded to the S7 controller.
Receive buffer overflow
1 = The receive buffer is full. At least one message was discarded.
Note: May only be evaluated when the transfer bit is "1".
Number of data bytes in the received CAN message
The value range is 0 to 8.
Note: May only be evaluated when the transfer bit is "1".
Transfer
If the bit is "1", a received message is transferred. The S7 controller should then set the
receive enable bit to "0".
Reserved, must be "0"
RTR flag of the received CAN message
0 = Normal data message
1 = RTR message
Note: May only be evaluated when the transfer bit is "1"
29/11-bit message ID of the received CAN message
0 = 11-bit message ID
1 = 29-bit message ID
Note: May only be evaluated when the transfer bit is "1".
Message ID of the received CAN message (in Big Endian)
For 11-bit message IDs byte 3 bit 2 is the most significant bit and byte 4 bit 0 the least
significant bit (the other bits are ignored).
For 29-bit message IDs byte 1 bit 4 is the most significant bit and byte 4 bit 0 the least
significant bit.
Note: May only be evaluated when the transfer bit is "1".
Data bytes of the received CAN message
In the order in which they were received.
Only the corresponding "Number of data bytes in the received CAN message" may be
evaluated.
Note: May only be evaluated when the transfer bit is "1"
Functions
4.2 CAN transparent
.
.
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