
MD-620 User Manual
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defined as shown above.
As a DTU, MD-620 connects to user’s serial device via its serial line
terminal. After MD-620 connects to mServer, user’s serial data acquisition
software connects to mServer via i.e. virtual serial port, and maps to the
terminal corresponding to RS232 channel (or RS485 channel). This way
implements the wireless and bi-directional data transmission between
user’s serial device and serial data acquisition software.
As a RTU, MD-620 supports MODBUS serial link protocol. MODBUS is a
master/slave protocol: the master station sends requests to the slave
station, and processes responses from the slave station; the slave station
receives requests from the master station, process the requests and send
responses to the master station. MD-620 RTU acts as the MODBUS slave
station, and software supporting MODBUS protocol acts as master station
and connects to mServer through DCC interface or virtual serial port, and
maps to the terminal corresponding to the MODBUS channel; thus the
software can send MODBUS data requests that meets with eTung’s RTU
MODBUS protocol, MD-620 RTU receives requests and returns MODBUS
responses. This way MODBUS master can monitor and control the status
of devices that connect to MD-620 RTU as MODBUS slave.
At the same time, according to user’s configuration, after MD-620
successfully connects to mServer, it can proactively upload GPS
information, or reactively response to GPS information query. GPS
data query software connects with mServer via interfaces such as DCC
or virtual serial port, and maps to the terminal corresponding to GPS
channel. Then the software can receive positioning information from
MD-620 via GPS channel; and the software can also request
positioning information by sending GPS query command via GPS
channel.
1.6 Specifications
1.6.1 Technical Parameters
Basic Parameters
Power Supply: +5 ~ +36V wide range of voltage input, with
terminal interface
Data interface: RS232 and RS485, 3.81mm terminal interface
Network:
2G: GSM/GPRS/EDGE/CDMA2000 1x