Volison IDM-7842MG User manual

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
Functional introduction
The Modbus protocol is the most widely used protocol in the electronic industrial
equipment, and now it has become a general industrial standard. Through this protocol,
Modbus devices (such as PLC, DCS, HMI, and instruments) can communicate with each
other through a network or serial port. But the Modbus protocol used in the serial port
and the Ethernet network is different, so a gateway is needed to complete the
communication conversion between the two protocols. IDM-7842MG is a modbus
gateway product dedicated to connecting Modbus TCP devices and Modbus RTU/ASCII
devices.
IDM-7842MG is an isolated Modbus gateway device with multiple network ports. It
integrates 5 port 10/100M switches and 2 serial port Modbus gateways. Users can use
any port and 2 port RS-485/232 serial port to convert Modbus TCP and Modbus
RTU/ASCII protocol. The 2 port RS-485/232 serial port has photoelectric isolation. It is
integrated with Modbus TCP, Modbus RTU and Modbus ASCII protocol, and the serial port
can be configured flexibly into RS-485 or RS-232 mode through software, which can
easily realize the connection between Modbus Ethernet device and Modbus serial device.
Product features
1, 32 bit ARM Cortex-m3 CPU
2, 5-Ports 10/100M Ethernet interface, with switch function
3, Support 2-Port RS-485/232 serial port, two serial port can set different baud rate
4. RS-485/232 serial port photoelectric isolation, 1500V isolation voltage, 600W surge
protection, 15KV electrostatic protection
5. Redundant DC9~30V or AC18~30V dual power input
6. Integrated IEEE 802.3 10Base-T,IEEE 802.3u 100Base-T(X),ARP, IP, ICMP, IGMP,
UDP, TCP, DHCP, DNS,MODBUS TCP, MODBUS RTU, MODBUS ASCII
protocol
7. Provide 4 mode of work:
RTU_ Master--TCP_ Slaver, TCP_ Master--RTU_ Slaver
ASCII_ Master--TCP_ Slaver, TCP_ Master--ASCII_ Slaver
8. Maximum support for 32 Modbus TCP master stations and 4 Modbus TCP slave stations
9. Support two Modbus RTU/ASCII master stations and Modbus slave communication
10. The automatic adaptive function of the time interval of the character
11, Provide ID mapping function to realize the management of host ID number
12. The local port, the target IP address, and the target port number can be set
13, Can be configured through Web Server, Telnet, MG Configuration tools
14, MG Configuration tools support
Windows98/me/NT/2000/XP/WIN7/WIN8/WIN10 operating system
15, DIN-Rail Mounting, industrial design, can run steadily in bad environment
Product specification
Ethernet
Standard: 5-Ports 10/100Mbps adaptive Ethernet port
Communication mode: full duplex / half duplex adaptive
Transmission distance: less than 100 meters
Interface type: RJ-45

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
Serial port
Interface: 2-Port RS-485/232, Photoelectric isolation
RS-232: T, R, G
RS-485: D+, D-
Parity bit: None\Even\Odd\space\mark
Data bits: 6bit, 7bit, 8bit
Baud rate: 300BPS to 230400bps
Direction control: RS-485 uses data flow direction automatic control technology
Load capability: RS-485 terminal support maximum 128 node polling
Transmission distance: RS-485 is 1000 meters,RS-232 is 10 meters
Interface protection: 1500V isolation, 600W surge protection, 15KV ESD protection
Power Supply
Power input: AC18~30V or DC9~30V, Double redundant input
Power consumption: 240mA @ 24V (Max)
Environmental
Working temperature: -20 C ~ 70 C
Storage temperature: -40 C ~ 95 C
Storage humidity: 5 ~ 95% RH
Package size
Restore the default settings
Hardware recovery: Press the Default key to restart the power and wait for 3 seconds
to undo the Default key to restore the factory settings.
Software recovery: Search the device through the MG Configuration tool software
and click to restore the factory settings button.

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
LED instructions
Power indication: "P1",”P2” bright yellow is the normal power supply
Serial Port 1 sending and receiving indication: "COM1" is Flash
Serial Port 2 sending and receiving indication: "COM2" is Flash
Interface definition
RS-232： COM1(T, R, G) / COM2(T, R, G)
RS-485： COM1 (D+, D-) / COM2(D+, D-)
Network interface: 5-Ports RJ45 (Ethernet)
Power interface: P1 (V+, V-), P2 (V+, V-)

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
Composition Principle
Configuration instructions
There are three configurations of IDM-7842MG, which are the Telnet console, the Web
server console, and the MG Configuration PC software configuration.
Web server console configuration instructions
1. Open the IE browser Enter the IP address of the IDM-7842MG Modbus gateway in the
address bar (default: 192.168.10.245)
2. Set the basic parameters
Gateway name：Device name (less than 11 characters).
Gateway address：The location of the device (less than 11 characters).
Web console："Enable" enables Web console, and "Disable" closes Web console.
Telnet console："Enable" enables Telnet console, and "Disable" closes the Telnet
console.
3. Network parameter configuration
MAC address：The MAC address of the IDM-7842MG device can not be changed.
IP address：The IP address of the IDM-7842MG device in the network.
Net mask：Subnet mask.
Gateway：Gateway address.

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
IP configuration：The type of IP address, DHCP: dynamic IP automatic acquisition,
Static: static IP address.
DNS server：When the target IP is a domain name, DNS server is the IP address of the
domain name resolution server.
4, Serial port configuration
Baud Rate：Serial baud rate, 300~230400 can be selected.
Data Bits：Serial data bit, 6,7,8 bit can be selected.
Stop Bits：The stop bit of the serial port can be selected as 1, 1.5, and 2 bits.
Parity：Parity bit, None\Even\Odd\space\mark can be selected, default is None
Timeout (Frame Interval Time): When the device is set to Modbus RTU protocol mode,
data frames are distinguished by serial idle time. If the serial idle time is longer than the
frame interval time, the Modbus Gateway confirms that a frame data has been received,
and then the frame data is checked and converted into TCP data frame and sent to
Ethernet. Timeout (Frame Interval Time) range is (0-15000) ms, set to 0 is automatically
adapted frame interval time.
Note: If multiple Modbus TCP master stations and Modbus gateways establish TCP
connections, or serial RS-485 bus access multiple Modbus RTU slave stations, Timeout
(Frame Interval Time) must be set larger, so that RS-485 slave stations can clearly
capture command frames sent by TCP master stations, and the recommended setting is
50ms.
Interface：Serial interface type, can choose RS-485, RS-232 two formats.

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
5, Modbus gateway operation mode configuration
IDM-7842MG Modbus Gateway provides 4 work mode:
(1), TCP_ Master-RTU_ Slaver: Network end connection Modbus TCP master station,
serial connects Modbus RTU slave station
(2), TCP_ Master-ASCII_ Slaver: Network end connection Modbus TCP master
station, serial port connects Modbus ASCII slave station
Max connection：The maximum number of connections allowed by Modbus TCP master
station is 32. Users can adjust this parameter according to the actual application. When
users do not need 32 connections, they can be reduced to improve performance. The
effective range of the maximum number of connections is 1~32. You need to change this
value when multiple TCP master stations or multiple RTU/ASCII slave stations.
Local TCP port： The default port number of the standard Modbus TCP protocol is 502,
and the user can modify it according to the actual application.
Message Timeout (Message Response Time): Modbus protocol is a master-slave
protocol. The master station waits for the slave station to respond after sending the
request. The range of Message Timeout (Message Response Time) is 100-32000ms, and
the default value is 200ms. When multiple TCP master stations communicate with
RTU/ASCII slave stations, the TCP master station will wait for the response of the
RTU/ASCII slave station after sending the request. If the RTU/ASCII slave station does
not respond within a set time, then the Modbus gateway will forward the request
instruction of the next TCP master station.
Serial Port 1: the setting of serial port 1
Serial Port 2: the setting of serial port 2
ID range：ID range. The two serial ports need to set different ID ranges. If the ID
number of the Modbus TCP master's data frame is not in the ID range of serial port 1 or
serial port 2, the frame data will be discarded. If the ID number of the data frame is in the
range of ID of serial 1, the frame data will be sent to the serial port 1. If it is in the range
of ID of the serial port 2, it will be sent to the serial port 2. The ID range of the serial port
1 and the ID range of the serial port 2 can not be repeated.
ID Mapping：ID mapping capabilities, optional AUTO and Fixed.

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
AUTO：When Auto ID is selected, the ID number in the Modbus TCP master station
request frame is not modified and will be sent directly to the serial port slave station
device.
Fixed： When Fixed ID is selected, the ID number in the Modbus TCP master station
request frame is replaced with a fixed ID number and then sent to the serial port slave
station device. The serial port slave station device returns the frame, it's ID number is
converted to before the change, and then to the Modbus TCP master station.
Fixed ID Value： Fixed ID number, when selecting Fixed, Modbus Gateway uses this
fixed ID number to access the serial port slave device, the range is 1~247.
(3), RTU_ Master-TCP_ Slaver: Network end connection Modbus TCP slave station,
serial port connection Modbus RTU master station, in this mode, all two serial ports can
connect to the Modbus RTU master station
(4), ASCII_ Master-TCP_ Slaver: Network end connection Modbus TCP slave station,
serial port connection Modbus ASCII master station, in this mode, all two serial ports can
connect to the Modbus ASCII master station
Destination IP address：When Modbus Gateway works in TCP_ Slaver mode, it can
support 4 Modbus TCP slave connections. Users can set IP address of target host to
connect Modbus TCP slave station. When the target connection is not used, the IP
address should be modified to 0.0.0.0. Otherwise, the Modbus Gateway device will
continuously send the connection request, so that it will affect the network
performance.When the target host address is a domain name, "/" is added before the
domain name, and "/" represents the domain name. The length must be less than 20
characters
Port：The port number of the target host, the default port number of the standard
Modbus TCP protocol is 502, and the user can modify it.
ID mapping:
Min ID/Max ID：The minimum value of ID and the maximum value of ID, and its range
is 0~247. When the serial Modbus master station connects TCP slave station, the Modbus
Gateway device will check whether the target is within the range, and if it is not in the
range, it will not be sent. Max ID can't be less than Min ID, otherwise it is treated as Min
ID. When Max ID<=Min ID, the Modbus Gateway device uses Min ID, and the ID range of
the 4 connections cannot be repeated, otherwise the error will occur.
ID offset：ID offset, the Modbus protocol stipulates that all slave station devices must

5-Ports 10/100M Ethernet Switch plus Isolated MODBUS
Gateway IDM-7842MG User's Manual
have a unique ID number (1~247), which is used to identify the slave station address.
The ID number of Modbus slave station device can be modified. When the Modbus serial
master station access the TCP slave station, the target ID will add the offset and then
sent to the Modbus TCP slave station. When the Modbus TCP slave station returns the
data, the offset is subtracted from the ID number and then sent to the serial port
MODBUS master station.
Technical support
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