Pre-Defined Layer 2 Receive Messages - Mitsubishi Electric MELSEC-F FX3U-CAN User Manual

FX -CAN User's Manual
3U
9.3.2

Pre-defined Layer 2 receive messages

This subsection describes parameters A to D for the receive message.
Parameter
Layer 2 message number parameter A Reception CAN-ID low word
Layer 2 message number parameter B Reception CAN-ID high word
Layer 2 message number parameter C Reception ID filter bit mask low word
Layer 2 message number parameter D Reception ID filter bit mask high word
1. Parameter A and B for each Layer 2 message
Set the source CAN ID of the received message to parameter A and B. CAN-ID is as follows, corresponding
to the function mode to be used.
When Layer 2 message number is not used, set HFFFF to both parameter A and B.
Function Mode
11 bit CAN-ID Layer 2 Mode
29 bit CAN-ID Layer 2 Mode
2. Parameter C and D for each Layer 2 message
Set the filter for the ID set in parameter A and B. If the filter is set to H00000000, incoming messages are
checked for an exact match with the ID set in parameter A and B. Any bit set in the filter will be omitted when
comparing received IDs with the ID set in parameter A and B.
Example 1:
Layer 2 message 1 parameter A/B = H00000181
Layer 2 message 1 parameter C/D = H00000000
BFM #100 to #106 store received messages with the CAN-ID H181 only. Relation between received CAN
message, BFM #20 bit 0 and "RTR/new/DLC" high byte is shown below.
CAN bus
BFM #20
bit 0
RTR/new/DLC
Hxx
high byte
The flags "RTR/new/DLC" are cleared by PLC program after
was no message stored between
and C/D is stored into the internal buffers, and as this is the only message between
value is set to H03. The high byte value H07 after
this example two times) since
Note
In this example, it is expected that the PLC program resets the "RTR/new/DLC" flags after reading the data at
, , and
Store CAN-ID in the 11 bits, bit 0 to 10, in the parameters A and B by 32 bit instructions.
Store CAN-ID in the 29 bits, bit 0 to 28, in the parameters A and B by 32 bit instructions.
Message
H0181
H00 (no new data
H00
between and
and
. The data bytes in the BFM are the data received with the last message.
.
9.3 Pre-defined Layer 2 Message Configuration
Description Initial Value
→ For function mode, refer to Section 6.5
Description
Message Message Message
H0181 H0181
H03 (new frame + data
) between and
. They remain H00 after
. The first received CAN message that matches parameter A/B
shows that the buffer was overwritten at least once (in
9 CAN Layer 2 Mode
HFFFF
HFFFF
H0000
H0000
H0181
H07 (new frame + data
and overflow between
)
and )
, because there
and , the high byte
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