Westermo EDW-100 - Manual (Page 29)

29 6616-2203
Applications
=Termination
EDW-100
Slave unit Slave unit Slave unit
EDW-100
Slave unit Slave unit Slave unit
Max 0.3 metre
=Termination
T+
T–
T+ T- T+ T- A B
R+
R–
T+
T–
R– R+ R+ T– T– B’ A’ B A T+ T+ R–
2-wire termination
4-wire termination
Termination recommendations
The RS-422/485 line must be terminated regardless of the cable length. The termination
is ideally placed at the extreme ends of the cable see examples above. The description
of the RS-422/485 pin outs will vary between manufactures. For some brands the T+
corresponds to A T- to B, R+ to A´ and R- to B´, but other brands might use some other
naming convention. If a unit does not work it can help to swap A and B. If difficulty is
being experience contact Westermo for further guidance.
RS-422/485 general advice
Power
SDRAM
8 MB
FLASH
2 MB
DIP-switch
JTAG
PROCESSOR DEBUG
Data
Address
CTRL MAC
XTAL
PHY
XTAL
CLK
RESET
5 V = >3.3
V
3.3 V = >1.5
V
Power
A
Power
B
Connector
I/O
I/O
RJ-45
LED
stretch
D-sub
SERIAL CH 1
Ethernet
1
Po
w
er secondar
y 5
V
RS-232
Screw terminal
RS-422/485
Isolation from all other interfaces
Buffer size
Transmit Buffer 8Kbyte.
Receive Buffer 8Kbyte.