Samsung SSA-P102 Connecting the Termination Resistor and Diode, Bypass Diode Connection

installation and external connection

CONNECTING THE TERMINATION RESISTOR AND DIODE

Termination Resistor

A resistor is inserted for matching the line’s impedance to prevent distortion and reduction in RS-422 or RS-485 long distance data communications, which is referred to as termination resistor.

Note that termination resistors of lower than 90 accepted for the communications system.

"	RS-485	RS-485		A
RS-485/RS-232
Converter
#	120Ω		120Ω	B
	Termination Resistors
				Last SSA-P102
	<Termination Resistor in RS-485 Communication>
			120Ω
	TX+		RX+
RS-485/RS-232	TX-		RX-
	RS-422	RS-422
Converter
	RX+		TX+
	RX-		TX-
120Ω				Last SSA-P102
	Termination Resistors

<Termination Resistor in RS-422 Communication>

Bypass Diode Connection

If you connected an inductor (door lock or alarm device) to the output relay, there should occur a voltage surge while the inductor was between turning on and turning off. If you do not connect a bypass diode to the relay, the voltage surge will cause damage to the electric circuit of the controller. To reduce this surge, it is recommended to connect a bypass diode to the relay.

DC+

DC-

SSA-P102Lock/Alarm

Cathode Anode

1N4004 ~ 1n4007 or equiv.

10_ installation and external connection