Access By Request Command - Mitsubishi Electric LE7-40GU Instruction Manual

Access by request command

For any access to data in LE7-40GU from the SLMP equipment, data can be read and written by handshake between the
"request command execution" flag and the "request command completion" flag.
Double word data from the SLMP equipment is used for this access.
This 2-word data is comprised of the request command, to which the upper 4 bits of the first word are assigned, and the
request code, to which the lower 2 bits are assigned, and the setting data, to which the next word is assigned.
bit 15 to 12
Request command
Setting data
There are three types of request command, Data Monitor, Writing to RAM, and Writing to RAM + ROM, according to the
selection of data reading and writing method.
Monitor
Writing data is reflected in the settings based on a
data read request from the SLMP equipment but is
not stored against power interruption.
Since there is a limit on the number of writable times in the ROM for power failure storage, it is necessary to write the data
where write updates are performed periodically from the PLC only to RAM.
Request command
H0
H1
H2
The request code indicates the data No. (address) of data for which the request command is executed. Also, the subsequent
data setting is the data to be written to that data number.
If the request command is a monitor, the data setting data is ignored.
When double word data is written to send data in the SLMP equipment, and the handshake is executed by turning ON/OFF
the request command execution flag and request command completion flag as follows, LE7-40GU sends back the request
command execution result.
If an error occurs, triggered by the request command from the SLMP equipment, the local station turns ON the network alarm
occurrence flag and outputs the device No. that has the error to the monitor of the device number of the network alarm.
1.
SLMP compatible device executes request command (D103, b15) ON.
2.
The LE7-40GU processes in accordance with the SLMP equipment request command execution ON.
3.
LE7-40GU turns ON the request command completion.
4.
The SLMP equipment receives request command completion (Dn+3, b15) ON.
5.
The SLMP equipment sets request command completion OFF.
6.
The LE7-40GU receives request command execution OFF from the SLMP equipment.
7.
LE7-40GU turns OFF the request command completion.
8.
The SLMP equipment receives turning OFF of the request command completion.
Please perform reading of the execution results of the request command between step 4 and 5 of the handshake procedure.
For the request command execution result, refer to the following.
LE7-CCL APPLICATION MANUAL
4 SLMP COMMUNICATION
44
4.2 Communication Setting
bit 11 to 0
Request code
Writing to RAM
Writing data is reflected in the settings based on a
data write request from the SLMP equipment but is
not stored against power interruption.
Contents of execution
Monitor
Writing to RAM
Writing to RAM + ROM
Writing to RAM + ROM
Execute data writing to the RAM + ROM (for
storage against power interruption).
Execution result
Monitored value
Writing result
Writing result