Memory Access Function - Panasonic MEWNET-F Technical Manual

8.1.2 Memory Access Function

In the CPU on the master station, data can be written to and read from the memory in teh advanced
units on a slave station installed on the slave unit.
The high-level instructions of sequence programs F152(RMRD) and F153(RMWT) are used.
(These instructions are called "Memory access instructions" in this chapter.)
The figure below shows an example of writing the data for the pulse output unit from the CPU or
monitoring the data with the memory access instructions.
Note:
-The maximum data length that can be written or can be read by the instructions given above is 32
words per instruction.
-While a memory access instruction is being executed (R9035: OFF), another memory access
instruction cannot be executed.
-There are some differences in the operations between the normal memory access instruction
F150/F151 and the memory access instruction F152/F153 for the advanced unit on a slave station.When
executing the memory access instructions F152 or F153, not the following:
- When using F150 or F151:
When the instruction is executed, the actual processing will be done and it will be completed (it will bake
one scan cycle before the processing is completed).
- When using F152 or F153:
When the instruction is exectued, data receive request or data send request is executed only for the
slave station system.The actual processing will be done when the END instruction is executed.
Therefore, it will take several scan cycles before the processing is completed.When you access the
memory of teh advanced unit, check the execution status by looking at the special relays and special
data register.
- R9035: RMRD/RMWT instruction executable flag
- R9036: RMRD/RMWT instruction end flag
- DT9036(DT90036): RMRD/RMWT instruction end code
-For information on the memory (address), refer to the manual of an advanced unit with memory.
"Memory" is the memory that advanced units have.Data and parameters for setting operations to be
used on advanced units are stored.Data can be read or written from the CPU.
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