12
Rev. 1.0
8/26/2015
STM11 Hardware Manual
RS-232 to RS-422/485 4-wire Converter:
•
UT-202
is a recommended ‘RS-232 to RS-422’ converter from UTEK TECHNOLOGY
(SHENZHEN) CO, LTD.
(http://www.szutek.cn/)
The connection is as follows. It only supports
to establish the full-duplex (4-wire) RS-422 network. It can’t be used in the half-duplex (2-wire)
RS-485 network.
DB9 Male
(PIN)
Converter
Output
Drive
1
T/R+
RX+
2
T/R-
RX-
3
RX+
TX+
4
RX-
TX-
5
GND
GND
USB to RS-422/485 4-wire Converter
•
UT-890
is a recommended ‘USB to RS-422/485’ converter from UTEK TECHNOLOGY
(SHENZHEN) CO, LTD.
(http://www.szutek.cn/)
The connection is as follows. It supports to
establish either the half-duplex (2-wire) RS-485 network or the full-duplex (4-wire) RS-422
network.
DB9 Male
(PIN)
Converter
Output
Drive
1
T/R+
RX+
2
T/R-
RX-
3
RX+
TX+
4
RX-
TX-
5
GND
GND
Two-Wire Configuration
In a 2-wire system, the host must disable its transmitter before it can receive data. This must
be done quickly before a drive begins to answer a query. The STM11 includes a transmit delay
parameter that can be adjusted to compensate for a host that is slow to disable its transmitter.
This adjustment can be made over the network using the TD command, or it can be set using the
ST Configurator software. It is not necessary to set the transmit delay in a four wire system.
to PC
to PC +
to PC GND
Drive#1
Drive#2
Drive#3
GND
GND
RX-
RX+
TX-
TX+
GND
RX-
RX+
TX-
TX+
RX-
RX+
TX-
TX+
120
RS-422/485: 2-wire system diagram
NOTE: If the PC does not have an RS-422/485 serial port, a converter will be required.
NOTE: DO NOT send SCL Command “PR261” to the drive with two-wire configuration.
