Siemens SIMATIC PN/CAN LINK Operating Instructions Manual page 78

Coding of the bits in "Criterion" and "Mask"
The bits in "Criterion" and "Mask" are coded as follows.
Note
For values made up of multiple bits, the first bit is the MSB and the last bit is the LSB.
Example: Bit 28 ... 27 = "2" means that bit 28 = "1" and bit 27 = "0"
Bit
31
30
29
28 ... 0 Message ID
Example:
If a filter is to be set so that only 29-bit data messages with message ID "0x?????9" are
received, the following conditions must be met:
• RTR for "Criterion" = 0 and "Mask" = 1
• 29/11-bit message ID for "Criterion" = 1 and "Mask" = 1
• Message ID for "Criterion" = 0x9 and "Mask" = 0xF
This means "Criterion" = 0x20000009 and "Mask" = 0x6000000F.
The bytes to be written as data record therefore are "0x20 0x00 0x00 0x09 0x60 0x00 0x00
0x0F".
Note
If less than 8 bytes are written or if bit 31 = "1" is true for "Criterion" for all filters, the receive
proxy has "no valid receive filter". That is signaled in the corresponding bit in the input data
for the S7 controller.
SIMATIC PN/CAN LINK
Operating Instructions, 03/2022, A5E39895388-AC
Meaning
Filter valid (only with "Criterion")
0 = Filter is valid
1 = Filter is invalid and is ignored by the PN/CAN LINK
For "Mask" the bit is reserved and must always be 0.
RTR
0 = Only data messages are entered in the receive buffer
1 = Only RTR messages are entered in the receive buffer
29/11-bit message ID
0 = Only CAN messages with 11-bit message ID are entered in the receive buffer
1 = Only CAN messages with 29-bit message ID are entered in the receive buffer
Only CAN messages with the message ID are entered in the receive buffer.
Note: For received CAN messages with 11-bit message ID, bits 28 ...11 in the message are
accepted as "0". If one of the bits 28 ... 11 is set in "Criterion" as well as "Filter", the filter will
not match any of the received 11-bit messages.
Functions
5.2 CAN transparent
77