Rs485 Wiring - Adeunis RF ARF33-PRO Instrucciones Para El Uso

3.3.

RS485 wiring

Wiring the RS485 bus only requires two cables:
• TX+ is connected to RX+.
• TX- is connected to RX- on the PCB.
In order to enable RS485 management, the switch SW 1.1 must be ON and the S215 value must be 1 (cf table
below).
PLEASE NOTE
The switch SW1.1 is only read at power on. No change to the SW1.1 switch (while the modem is operating) will
be recognised.
S215 value
1
1
0
Table 1: R485/232 configuration settings
By default, the DE and RE lines are declared LOW, thus permitting reception of characters from the RS485 dif-
ferential bus. The DE and RE lines are only declared HIGH when one or more characters need to be transmitted
by the RS485 differential bus: when a radio frame is demodulated, the lines are declared HIGH, then the data
extracted from the radio frame is sent to the TXD module, and as a consequence to the RS485 differential bus.
When the last character has been transmitted on the RS485 differential bus, the lines are declared LOW.
Figure 1: DE/RE timing when data is sent over the serial link
Threshold: minimum = 1 µs
208210A_UG_V1.6_ARFx3-PRO
BUS RS485 NAME
+ Vcc
GND
A TX+/RX+
B TX-/ RX-
Connect only TX-
or RX- (note 1)
Note 1:
 TX- is connected to RX- on the PCB
 TX+ is connected to RX+ on the PCB
SW1.1
ON
OFF
ignored
TXD
Tde
RE/DE
+
INHIB
-
RTS
Connect only
RX
TX+ or RX+ (note
TX
1)
CT
S
TX+
TX-
ON
RX+
RX-
1 2
Note
RS485 command line management
RS232 configuration
RS232 configuration
Data
Threshold 1µs
31