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4 USER GUIDE
4.5
SV.LINK System Programs
This section explains the system programs shown in Section 4.4, "Software Configuration of
SV.LINK".
The system programs are classified into the four types listed below. All program runs on a
SV.LINK module.
High-speed I/O communication program
UDP program
IP program
Driver
4.5.1 High-speed I/O communication program
The high-speed I/O communication program uses the MELSEC's fixed-buffer communication
function (asynchronous) to transmit the data from a user-defined transmission area and writes
the data received from the MELSEC to a reception area.
The UDP port opening signal, UDP transmissions, and UDP receptions are passed to the UDP
program via memory interface and processed.
4.5.2 UDP program
The UDP program as a higher-level protocol manages high-speed transmission/reception of a
large amount of data.
The UDP program has the following functions:
Connectionless communication
Simultaneous communication
Packet-based data transmission
4.5.3 IP program
The IP program as a low-level protocol conducts logical connection of communication paths.
The IP program has the following functions:
Disassembling or reassembling data according to the maximum packet length
Exchanging IP address and physical address
4.5.4 Driver
The driver controls the communication circuit, and sends data to and receives data from lines
(transceivers).
The driver has the following functions:
CRC (Cyclic Redundancy Check) for transmission/reception of data
Data collision detection during transmission/reception and retransmission
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