GearMo GM-482422 User manual

GearMo GM-482422
USB TO RS-485/422 Interface Converter User Manual
Introduction
Compatible with the Recommended Standards of USB, RS-422 and RS-485, GM-482422 photoelectric isolation interface
converter can convert the single-ended USB signal into balance differenced RS-422 or RS-485 signal.
The GM-482422 USB to RS-485 or 422 Converter’s built-in photoelectric isolator can
provide an isolation voltage of as high as 2500Vrms. It is also manufactured with a
rapid transient voltage suppression protector; this is protection for the RS-422 or RS-
485 interface developed with advanced TVS (Transient Voltage Suppressor)
technology adopted.
Under normal operating conditions, the TVS tube is in the state of high
resistance. However, when both ends of the TVS tube are hit by a transient high
energy, the impedance at both ends can be suppressed by the TVS at a very high
speed. After absorbing a high current, the voltage between the two ends is
suppressed and kept at a pre-set value; therefore no damage is caused to the
electrical components behind by the transient high voltage impact.
The surge protection in the USB to RS-485 converter can effectively restrain lightning or ESD (electrostatic discharge)
with a protection voltage of 600W on each line for lightning surge, surge voltage, or transient over-voltage possibly
caused by other electrical sources. In this case, the USB to serial converter will maintain the high-speed transmission of
RS-422 or RS-485 interface ensured by the tiny capacitance between the poles.
RS-422 and RS-485 Interfaces
RS-422 and RS-485 interfaces with a DB9 male connector that is to be used
for connection. The internal zero delay auto transceiver contained in the
unique I/O circuit, controls the RS-422 converter’s data stream direction
automatically. No handshaking signal required (for example RTS, DTR etc).
The GM-482422 USB to serial converter is plug-and-play, no jumper settings
needed for mode shift between full duplex (RS-422) and half duplex (RS-
485). The converter is applicable for the existing communication
software/hardware interface.
A reliable and stable point-to-point and point-to-multipoint communication can be ensured by GM-482422 photoelectric
isolation interface converter. For point-to-multipoint communication, as many as 32 interface facilities of RS-422 or RS-
485 standard can be connected to each converter with a high 300-921.6KBPS data transmission rate. LED indicators for
Power and Data are also available with the converter for malfunction indication. Two conversion communication
modes including USB to RS-422 and USB to RS-485 are supported.

Performance Parameters
USB Version 1.0, 1.1, and 2.0 Standards compliant
Serial Signal Supported
RS-485, RS-422 TIA/EIA Standard
USB Signal
VCC DATA+, DATA-, GND, FG
RS-485 Signal
T/R+, T/R-, GND
RS-422 SignalTXD+, TXD-, RXD+, RXD-, GND
Working Mode:Asynchronous working, point-to-point or point-to-multipoint 2 wires (half duplex)
4 wires (full duplex)
Direction Control
Adopt the technology which automatically controls the data-flow ddirection,
automatically distinguish and control the data-transmission direction.
Transmission Rate 300-921600bps, Automatically detect the serial port signal rate
Load Capability
Support point-to-multipoint transmission. Each converter can connect 32 RS-422
or RS-485 interface equipment
Transmission Distance RS-485/422 port: 1.2km (921600bps-300bps).USB port: No more than 5 meters.
Interface Protection
600W lightning strike and surge protection and ±15KV ESD
protection.
Interface form
USB port: A type male interface. RS-485/422 port: 5-pin connection pole.
Signal Indication
3 LED’s for Power(PWR), Send(TXD), and Receive (RXD)
Transmission media Twisted-pair cable or shielded cable.
Dimensions 62mm x 33mm x 19mm
Working environment -40° to 85
℃
, relative humidity 5% to 95%.
Operating System Windows95/98/2000/XP/Vista, IMAG supported.
Connector and Signal
RS-485, RS-422 data output, connector, and bay-line distribution.
Connection pole Data Output RS-422 Full-Duplex RS-485 Half-Duplex
1 T/R+ Send (A+) RS-485 (A+)
2 T/R- Send (B-) RS-485 (B-)
3 RXD+ Receive(A+) N/C
4 RXD- Receive(B-) N/C
5 GND Ground Wire Ground Wire

USB to RS-422 and RS-485 Schematic Diagrams
USB to RS-422 Conversion
RS-422 point-to-point 4 wires full-duplex
RS-422 point-to-multipoint 4 wires full-duplex
USB to RS-485 Conversion
RS-485 point-to-point 2 wires half-duplex
RS-485 point-to-multipoint 2 wires half-duplex

Problem and Resolution
Data communication failure
1. Make sure USB interface connection is correct.
2. Make sure RS-485/RS-422 output interface
connection is correct.
3. Make sure power supply is OK.
4. Make sure the wire terminal connection is OK.
5. Make sure the pilot lamp flashes when receiving.
6. Make sure the pilot lamp flashes when sending.
Data missing or incorrect Check to see whether if the data rate and format at both
ends of the communication equipment are consistent.