Helmholz 700-651-CAN01, Руководство пользователя

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Each transmit or receive object can be defined for exactly one
CAN message. The length of the CAN message corresponds to the
size of the DI/DO object. The CAN ID is defined in the parameter
set.
4.6 Parameterizing the Receive Object
The Receive Object must also be parameterized if it is to be used.
4.6.1 11-bit protocol
In order to receive any CAN frames with the Receive Object the
upper 8 bits of the CAN identifier are first filtered with a mask
(acceptance mask) and then compared with a predefined value
(acceptance code). If this comparison is positive, the CAN frame is
entered in the Receive FIFO and the PLC is released.
10 9 8 7 6 5 4 3 2 1 0
Received CAN identifier
AcceptanceMask (e.g. 11110000)
AcceptanceCode (e.g. 1011xxxx)
ignored
Acceptance Mask 11110000 (= 240) filters out the top 4 bits.
Acceptance code 1011xxxx (= 176) defines which frames are to be
accepted after filtering.
In this example it is the CAN frames with identifiers 0x580 to
0x5FF.
18 DP/CAN Coupler