User Manual - JVL Industri Elektronik A/S

3.15 RS485 Interface
The controller include RS485 beside the normal RS232 interface. The RS485 interface is intended for
purposes where 1 to 32 controllers are connected at the same line in a noisy environment.
B / -
Terminator
Connect to A if
Controller is the last
Unit on the line
9
8
5
4
Signal ground
A / +
TT0059GB
The communication protocol is exatly the same as RS232. The only difference is the balanced signallines,
end the fact that all communication is half duplex wich means that the controller can not send and
receive at the same time as by use of RS232.
The RS485 interface makes it possible to connect up to 32 units at the same lines.
At the last controller the terminal called Terminator (pin 8) must be shorted to the A terminal (pin 4).
Following illustration shows a typical system with 2 or more units connected to a computer or similar.
Controller
Address 1
Controller
Address 2
Master
Computer, PLC
or similar
GND
B / -
A / +
5 5
9 9
4
8 4
Terminator
To controller 3....32
Connect to A if
Controller is the last
Unit on the line
TT0060GB
The RS485 feature is available at controllers with serial numbers higher than 5500.
JVL Industri Elektronik A/S - User Manual - AC servocontroller AMC10/11/12 41