Functions
5.2 CAN transparent
SIMATIC PN/CAN LINK
Operating Instructions, 03/2022, A5E39895388-AC
75
Byte.Bit
Meaning
0.0
Transfer
If the bit is "1", a received message is transferred. The S7 controller should then set the
receive enable bit to "0".
1.7
Reserved, must be "0"
1.6
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"
.
1.5
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".
1.4 ...
4.0
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".
5-12
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"
.
Note on the use of a receive proxy
Representation of bits
1.
"Receive enable" is a bit that can be used to copy data to the SIMATIC S7 controller (you can
control this bit).
2.
"Message exists" is a bit that signals that there is a message in the input buffer.
3.
"Transfer" signals that the current position from the input buffer is actively transferred to the
SIMATIC S7 controller.
Procedure
1.
Set "Receive enable" to "1" and wait until "Message exists" is also "1".
2.
When this happens, the first message is copied to the SIMATIC S7 controller and "Transfer" is
set to "1".
3.
Set "Receive enable" to "0" and wait until "Transfer" is set to "0".
4.
Repeat the operation starting at step 1.
Содержание SIMATIC PN/CAN LINK
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