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 are not allowed, neither more than one termination resistor is accepted for the communications system.

RS-485/

￿

RS-485

RS-485

A

 

 

 

 

RS-232

 

 

 

 

Converter

￿

120Ω

120Ω

B

 

 

Termination Resistors

 

 

<Termination Resistor in RS-485 Communication>

SSA-P400(401)

 

 

 

 

 

120Ω

 

 

TX+

RX+

 

RS-422/

 

TX-

RX-

 

 

RS-422

RS-422

 

RS-232

 

RX+

TX+

 

Converter

 

RX-

TX-

 

 

 

 

 

120Ω

 

SSA-P400(401)

 

 

Termination Resistors

 

<Termination Resistor in RS-422 Communication>

CONNECTION EXTERNAL AND INSTALLATION

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+

 

Cathode

Anode

 

DC-

1N4004 ~ 1n4007 or equiv.

SSA-P400(401)

Lock/Alarm

 

English _ 13