Mitsubishi Electric MELSEC-L SERIES Basic User Manual page 24

(5) Exchange of data with connected devices (communications using a fixed
buffer and random access buffer)
(a) Communications using a fixed buffer
Up to 1K-word data can be exchanged among programmable controllers or between a programmable
controller and the host system. While MC protocol communications are passive, communications using a fixed
buffer are an active protocol. If an error occurs in equipment or certain conditions are met, the programmable
controller can send data to the host system. Using an interrupt program allows the CPU module to quickly read
received data. (
(b) Communications using a random access buffer
Up to 6K-word data can be communicated. This buffer is useful when the data size is too large for
communications using a fixed buffer (capacity: 1K word). (
(6) Prevention of unauthorized access through the IP filter
The IP address of the connected device to be allowed or denied access is set in the buffer memory, and access
from connected devices is restricted. (
(7) Prevention of unauthorized access through a remote password
This function prevents unauthorized remote access to the CPU module. The E71 checks an entered remote
password in data communications from a connected device using remote password-protected connection.
( Page 181, Section 14.4)
22
Page 120, CHAPTER 12)
Send/receive
Another station
Read/write
Connected device
Send/receive
Own station
Connected device
Page 154, CHAPTER 13)
Read/write
E71
Connected device
Page 175, Section 14.3)