Table of Contents
Advertisement
Chapter 9: Description for Data Link Operation
The data link function is used to send and receive ON/OFF signals (relay link) and data (register link)
between modules by assigning one module from PCs or FA devices as the master station and other
units as slave stations in the satellite net system. Up to 64 sets of PCs and FA devices can be
connected in the satellite net.
Each station sends data in its sending area cyclically and stores data received from other stations in its
receiving area. For the JW-21MN to execute automatically these sending and receiving procedures, a
special program for communications is required.
When the JW-21MN is assigned as a slave station, it has the standard function and save memory
function for data link, but the data contents for receiving from other stations is different between these
two functions. (When the JW-21MN is used as a master station, only the standard function is available.)
[When all of a master station and slave stations are JW-21MN]
- Master station
- Slave station
For the standard function and the save memory function of the JW-21MN, see page 15-2.
9-1 Communication method
[1] Data link (Standard function)
Each station cyclically sends and receives ON/OFF signals and data of the relay link area and register
link area set to a master station parameter.
(1) Relay link
Mainly used for sending and receiving ON/OFF information
[Example] In the case of sending 1-byte data from a master station and slave stations 01 and 02.
Master station (PC00)
コ０２００
コ０２０１
コ０２０２
PC00 Program
02000
02010
02020
- The link relay of the receiving station must be programmed as input signal by the PC program-
ming. Also, it may be used as source (S) side of application instruction.
- The sending and receiving data correspond in bits of one point unit.
７
６
コ０２００
７
６
コ０２０１
Is the same value as
Data link (Standard function)
Data link (Standard function)
Data link (Save memory function)
Slave station (PC01)
PC01 Program
02000
02010
02020
(Master station)
５
４
３
２
１
０
５
４
３
２
１
０
0201 of the slave station.
ｺ
9-1
Receiving data of all of the relay link area and
｝
all of the register link area of all the stations.
In order to effectively use the
memory, unify a partial data area or
sending/receiving address (program)
of slave stations.
Slave station (PC02)
PC02 Program
02000
02010
02020
(Slave station)
７
６
５
４
コ０２００
Is the same value as
７
６
５
４
コ０２０１
：
Send
：
Receive
３
２
１
０
0200 of the master station.
ｺ
３
２
１
０
9
Advertisement
Table of Contents
