Mitsubishi Electric CANopen ME3CAN1-L, Руководство пользователя

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Detailed Description of the Module Buffer Memory Overview
3 – 12 MITSUBISHI ELECTRIC
3.4 Buffer Memory Overview
The CANopen module has a memory range assigned as a buffer for temporary storage of data, such
as Received Process Data or CAN transmission error counter. The PLC CPU can access this buffer and
both read the stored values from it and write new values to it which the module can then process
(Transmit Process Data etc.).
Each buffer memory address consists of 16 bits.
The "Default" value indicated in the following tables is the initial value set after the power is turned on
or the PLC CPU is reset.
Instructions for data exchange with the buffer memory
Communication between the PLC CPU and the buffer memory of special function modules is per-
formed with FROM and TO instructions.
The buffer memory of a special function module can also be accessed directly, e. g. with a MOV
instruction. The special function module addressed in this way can be mounted on a base unit or an
extension base unit but not in remote I/O stations.
Format of the device address: Un\Gn
– Un: Head address of the special function module
– Gn: Buffer memory address (decimal)
For example the device address U3\G11designates the buffer memory address 11 in the special func-
tion module with the head address 3 (X/Y30 to X/Y3F).
In this User's Manual the latter form of addressing is used throughout.
For full documentation of all the instructions with examples please refer to the Programming Manual
for the MELSEC System Q and the L series.
Fig. 3-7: Assignments of bits to a buffer memory address
NOTE Do not write data in the "system areas" of the buffer memory. If data is written to any of the system
areas, the PLC system may not be operated properly. Some of the user areas contain partially sys-
tem areas. Care must be taken when reading/writing to the buffer memory.
Also, do not write data (e.g. in a sequence program) to the buffer memory area where writing is
disabled. Doing so may cause malfunction.
NOTE As long as Un\G25 bit 7 is ON ("Module is in initialization state"), any write access to the buffer
memory is prohibited and will generate a Un\G29 bit 5 error. Refer to section 3.5.7.
Bit
Buffer memory address