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11-3
4
3
2
1
0
F
E
D
C
B
A
9
8
7
6
5
(Factory setting: OFF)
ON
OFF
LT
(Rear side)
(4) Termination resistance switch (LT)
When the JW-21MN is at the termination station of the communication line, make sure to set the
termination resistance switch to "ON."
(Factory setting: 00)
(Front side)
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
110
STA NO.STA NO.
(3) Station number switch (STA NO.)
Make sure to set the master station number to "00." For slave stations, set from "01" to "77" in
octagonal sequence.
ON
OFF
Setting
Condition of the JW-21MN
Insert a termination resistance
Do not insert a termination resistance
- Maximum amount of slave stations to be connected are
63. As the station number should be assigned by
octagonal figures, setting of the following values causes
errors and the JW-21MN cannot communicate.
08, 09, 18, 19, 28, 29, 38, 39, 48, 49, 58, 59, 68, 69, and
78 to 99.
- Be careful that there is no doubly allocated number and no
number has been skipped.
-When using a termination (ME-75 made by Toko
Denshi) (device to function as terminator) at the end
of a signal cable, turn "OFF" the termination resis-
tance switch of the termination station.
Reference Need for the termination resistance
When a termination resistance is not provided at a communication circuit end, the end of the circuit
generates reflection waves. These reflection waves collide with sending signals and abnormal
communication may occur. The termination resistance prevents the occurrence of these reflection
waves. On the other hand, when an intermediate station has its termination resistance switch turned
"ON," this station causes reflection and attenuates signals and causes abnormal communication.
Termination
(ME-75)
Termination
Termination
1 km max.