MGate MB3170/MB3270 Series

Features and Benefits

  • Supports Auto Device Routing for easy configuration
  • Supports route by TCP port or IP address for flexible deployment
  • Connects up to 32 Modbus TCP servers
  • Connects up to 31 or 62 Modbus RTU/ASCII slaves
  • Accessed by up to 32 Modbus TCP clients (retains 32 Modbus requests for each Master)
  • Supports Modbus serial master to Modbus serial slave communications
  • Built-in Ethernet cascading for easy wiring
  • 10/100BaseTX (RJ45) or 100BaseFX (single mode or multi-mode with SC/ST connector)
  • Emergency request tunnels ensure QoS control
  • Embedded Modbus traffic monitoring for easy troubleshooting
  • Serial port with 2 kV isolation protection (for “-I” models)
  • -40 to 75°C wide operating temperature models available
  • Supports redundant dual DC power inputs and 1 relay output


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The MGate MB3170 and MB3270 are 1 and 2-port Modbus gateways, respectively, that convert between Modbus TCP, ASCII, and RTU communications protocols. The gateways provide both serial-to-Ethernet communication and serial (master) to serial (slave) communications. In addition, the gateways support simultaneously connecting serial and Ethernet masters with serial Modbus devices. The MGate MB3170 and MB3270 Series gateways can be accessed by up to 32 TCP master/clients or connect to up to 32 TCP slave/servers. Routing through the serial ports can be controlled by IP address, TCP port number, or ID mapping. A featured priority control function allows urgent commands to obtain an immediate response. All models are rugged, DIN-rail mountable, and offer optional built-in optical isolation for serial signals.

Integrate TCP Masters without Altering the Modbus RTU/ASCII Network or Software

The MB3270 can integrate Modbus TCP with Modbus RTU/ASCII, without modifying the existing Modbus RTU/ASCII architecture or software. With the serial redirector function, a serial master can maintain direct access to serial slave devices through a specially mapped serial port. This allows the serial and TCP masters to access serial slaves simultaneously.

Optical Fiber for Ethernet Communication

The MGate MB3170 Series includes 100BaseFX fiber models that support transmission distances up to 4 km for multi-mode models, and up to 40 km for single-mode models. Optical fiber is well-suited for industrial applications because it is immune to electromagnetic noise and interference. For environments that experience high ground loop voltages, fiber provides the best isolation protection, and because there is no danger of sparking, optical fiber is safer than copper wire to use in hazardous environments.

Auto-Device Routing for Easy Configuration (Patent Pending)

Moxa’s Auto-Device Routing function helps eliminate many of the problems and inconveniences encountered by engineers who need to configure large numbers of Modbus devices. A single mouse click is all that’s required to set up a slave ID routing table and configure Modbus gateways to automatically detect Modbus requests from a supervisory control and data acquisition (SCADA) system. By removing the need to manually create the slave ID routing table, the Auto-Device Routing function saves engineers significant time and cost.

Priority Control for Urgent Commands (Patented)

As Modbus networks increase in size and complexity, the lag time between commands and responses becomes a major concern. Advanced models of the MB3000 Series provide a priority control function for urgent commands, allowing users to force certain commands to get an immediate response. Depending on your system’s requirements, different methods are available to define which commands receive priority.

Patent Numbers: (US/TW)

  • US7,743,192 B2/I332618

  • US7,725,635 B2/I321007


Ethernet Interface
10/100BaseT(X) Ports (RJ45 connector) 2 (1 IP, Ethernet cascade)
Auto MDI/MDI-X connection
Magnetic Isolation Protection 1.5 kV (built-in)
Optical Fiber
Multi-Mode Single-Mode
Fiber Cable Type OM1 50/125 µm G.652
800 MHz x km
Typical Distance 4 km 5 km 40 km
Wavelength Typical (nm) 1300 1310
TX Range (nm) 1260 to 1360 1280 to 1340
RX Range (nm) 1100 to 1600 1100 to 1600
Optical Power TX Range (dBm) -10 to -20 0 to -5
RX Range (dBm) -3 to -32 -3 to -34
Link Budget (dB) 12 29
Dispersion Penalty (dB) 3 1
Note: When connecting a single-mode fiber transceiver, we recommend using an attenuator to prevent damage caused by excessive optical power.
Note: Compute the “typical distance” of a specific fiber transceiver as follows: Link budget (dB) > dispersion penalty (dB) + total link loss (dB).
Ethernet Software Features
Industrial Protocols Modbus TCP Client (Master), Modbus TCP Server (Slave)
Configuration Options Web Console (HTTP), Device Search Utility (DSU), MGate Manager, Telnet Console
Management ARP, DHCP Client, DNS, HTTP, HTTPS (MGate MB3180 Excluded), SMTP (MGate MB3180 Excluded), SNMP Trap (MGate MB3180 Excluded), SNMPv1/v2c/v3, TCP/IP, Telnet, UDP, NTP Client (MGate MB3180 Excluded)
MIB RFC1213, RFC1317
Time Management NTP Client (MGate MB3180 Excluded)
Serial Interface
No. of Ports MGate MB3170 Series: 1
MGate MB3270 Series: 2
Connector MGate MB3170/MB3170I: DB9 male for RS-232 and terminal block for RS-422/485
MGate MB3270/MB3270I: 2 x DB9 male
Serial Standards RS-232/422/485 (software selectable)
Baudrate 50 bps to 921.6 kbps
Data Bits 7, 8
Parity None, Even, Odd, Space, Mark
Stop Bits 1, 2
Flow Control DTR/DSR, RTS Toggle (RS-232 only), RTS/CTS
RS-485 Data Direction Control ADDC® (automatic data direction control)
Pull High/Low Resistor for RS-485 1 kilo-ohm, 150 kilo-ohms
Terminator for RS-485 120 ohms
isolation MGate MB3170I: 2 kV (I models)
MGate MB3170I-T: 2 kV (I models)
MGate MB3170I-M-SC: 2 kV (I models)
MGate MB3170I-M-SC-T: 2 kV (I models)
MGate MB3170I-S-SC: 2 kV (I models)
MGate MB3170I-S-SC-T: 2 kV (I models)
MGate MB3270I: 2 kV (I models)
MGate MB3270I-T: 2 kV (I models)
Serial Signals
RS-422 Tx+, Tx-, Rx+, Rx-, GND
RS-485-2w Data+, Data-, GND
RS-485-4w Tx+, Tx-, Rx+, Rx-, GND
Serial Software Features
Industrial Protocols Modbus RTU/ASCII Master, Modbus RTU/ASCII Slave
Modbus (Transparent)
Max. No. of Client Connections 32
Max. No. of Server Connections 32
Power Parameters
Input Current MGate MB3170/MB3270: 435 mA @ 12 VDC
MGate MB3170I/MB3170-S-SC/MB3170I-M-SC/MB3170I-S-SC: 555 mA @ 12 VDC
MGate MB3270I/MB3170-M-SC/MB3170-M-ST: 510 mA @ 12 VDC
Input Voltage 12 to 48 VDC
Power Connector 7-pin terminal block
Contact Current Rating Resistive load: 1 A @ 30 VDC
Physical Characteristics
Housing Plastic
IP Rating IP30
Dimensions (with ears) 29 x 89.2 x 124.5 mm (1.14 x 3.51 x 4.90 in)
Dimensions (without ears) 29 x 89.2 x 118.5 mm (1.14 x 3.51 x 4.67 in)
Weight MGate MB3170 Series: 360 g (0.79 lb)
MGate MB3270 Series: 380 g (0.84 lb)
Environmental Limits
Operating Temperature MGate MB3170: 0 to 60°C (32 to 140°F)
MGate MB3170-T: -40 to 75°C (-40 to 167°F)
MGate MB3170-M-SC: 0 to 60°C (32 to 140°F)
MGate MB3170-M-SC-T: -40 to 75°C (-40 to 167°F)
MGate MB3170-M-ST: 0 to 60°C (32 to 140°F)
MGate MB3170-M-ST-T: -40 to 75°C (-40 to 167°F)
MGate MB3170-S-SC: 0 to 60°C (32 to 140°F)
MGate MB3170-S-SC-T: -40 to 75°C (-40 to 167°F)
MGate MB3170I: 0 to 60°C (32 to 140°F)
MGate MB3170I-T: -40 to 75°C (-40 to 167°F)
MGate MB3170I-M-SC: 0 to 60°C (32 to 140°F)
MGate MB3170I-M-SC-T: -40 to 75°C (-40 to 167°F)
MGate MB3170I-S-SC: 0 to 60°C (32 to 140°F)
MGate MB3170I-S-SC-T: -40 to 75°C (-40 to 167°F)
MGate MB3270: 0 to 60°C (32 to 140°F)
MGate MB3270-T: -40 to 75°C (-40 to 167°F)
MGate MB3270I: 0 to 60°C (32 to 140°F)
MGate MB3270I-T: -40 to 75°C (-40 to 167°F)
Storage Temperature (package included) -40 to 85°C (-40 to 185°F)
Ambient Relative Humidity 5 to 95% (non-condensing)
Standard and Cerifications
EMC EN 55032/24
EMI CISPR 32, FCC Part 15B Class A
EMS IEC 61000-4-2 ESD: Contact: 6 kV; Air: 8 kV
IEC 61000-4-3 RS: 80 MHz to 1 GHz: 10 V/m
IEC 61000-4-4 EFT: Power: 4 kV; Signal: 2 kV
IEC 61000-4-5 Surge: Power: 2 kV
IEC 61000-4-6 CS: 10 V
IEC 61000-4-8 PFMF
IEC 61000-4-11 DIPs
Hazardous Locations ATEX, Class I Division 2, IECEx
Maritime DNV-GL
Freefall IEC 60068-2-32
Shock IEC 60068-2-27
Vibration IEC 60068-2-6, IEC 60068-2-64
Safety EN 60950-1, IEC 60950-1, IEC 62368-1, UL 62368-1
Time MGate MB3170/MB3170I Series: 1,349,710 hrs
MGate MB3170-M-SC/M-ST/S-SC Series: 1,175,887 hrs
MGate MB3170I-M-SC Series: 768,343 hrs
MGate MB3170I-S-SC Series: 763,707 hrs
MGate MB3270/MB3270I Series: 1,236,384 hrs
Standards Telcordia SR332
Warranty Period 5 years
Details See