Sharp JW-21MN manual 11-3, Station number switch STA no, Termination resistance switch LT

(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.

-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

78to 99.

-Be careful that there is no doubly allocated number and no number has been skipped.

STA NO.				STA NO.
6	7	8		6	7	8
			9			9
5			0	5		0
4	3		1	4	3	1
		2	×10			2

(Factory setting: 00)

×1

(Front 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."

Turn ON the termination resistance switches for these two stations.

			3456
			2	7
			01	8
			F
			E	A9
			DCB
Setting	Condition of the JW-21MN
ON	Insert a termination resistance	ON
OFF	Do not insert a termination resistance		LT
		OFF
- When using a termination (ME-75 made by Toko		(Factory setting: OFF)
Denshi) (device to function as terminator) at the end
of a signal cable, turn "OFF" the termination resis-
tance switch of the termination station.				(Rear side)
Termination		Termination

	1 km max.
	Termination
	(ME-75)
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.

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11-3