ProSoft PLX31-MBTCP-MBS4 Modbus TCP/IP to Modbus Serial 4 Port Gateway

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Manufacturer: ProSoft
Product No.: PLX31-MBTCP-MBS4
Country of origin:United States
Product Type: Protocol Gateways
Payment: T/T, Western Union
Weight: 2500g
Dimensions: 13.67 x 5.05 x 11.13 cm
Shipping port: Xiamen
Warranty: 12 months

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Description

Facilitating seamless bidirectional communication between Ethernet and serial-based field networks, the ProSoft PLX31-MBTCP-MBS4 acts as a robust protocol converter for industrial automation systems. This module enables a Modbus TCP/IP client or server to interface directly with up to four independent Modbus Serial networks, bridging the gap between legacy serial instruments and modern Ethernet control architectures. Engineered for high-reliability environments, it provides galvanic isolation on all communication paths and features a rugged, compact enclosure designed for DIN-rail mounting. With integrated diagnostics, a flexible power supply input, and individual port configuration, this gateway ensures low-latency data transmission across diverse factory automation, water treatment, and power distribution infrastructures.

Features

Independent Serial Ports: Four fully isolated serial ports supporting RS-232, RS-422, or RS-485 physical layers.
High Electrical Isolation: 2500 Vrms port-to-port and port-to-backplane signal isolation via digital RF modulation components.
Robust Ethernet Interface: Single 10/100 Mbps RJ45 port featuring 1500 Vrms electrical isolation and integrated broadcast storm resiliency.
Flexible Power Input: Accepts a wide input range of 10 to 36 VDC, suitable for standard industrial 24 VDC control panels.
Diagnostic Indicators: Front-panel LEDs provide immediate visual confirmation of power, module status, network activity, and serial transmission (TX/RX) status.

Applications

Integration of legacy Modbus RTU/ASCII power meters, flowmeters, and protection relays into modern Ethernet-based SCADA systems.
Substation automation where high electrical isolation is necessary to prevent ground loops and protect centralized controller CPUs.
Distributed water and wastewater monitoring setups requiring multi-point RS-485 serial networks linked to a centralized PLC over fiber or wireless Ethernet.

Technical Specifications

Manufacturer	ProSoft Technology
Model Reference	PLX31-MBTCP-MBS4
Power Supply Input	24 VDC nominal (10 to 36 VDC permitted)
Current Consumption	300 mA @ 24 VDC nominal (610 mA maximum @ 10 VDC)
Ethernet Port	1x 10/100 Base-T RJ45 connector, half/full-duplex auto-negotiation
Ethernet Isolation	1500 Vrms (50 to 60 Hz for 60 seconds)
Serial Interface Ports	4x isolated serial ports (RS-232, RS-422, or RS-485 configuration)
Serial Port Isolation	2500 Vrms signal isolation (UL 1577 rated, RF modulation media)
Operating Temperature	-25 to 70 degC (-13 to 158 degF)
Storage Temperature	-40 to 80 degC (-40 to 176 degF)
Relative Humidity	5% to 95% RH (non-condensing)
Shock Rating	IEC 60068-2-27: 15G operational (11ms), 30G non-operational (18ms)
Vibration Rating	IEC 60068-2-6: 5G @ 10 to 150 Hz
Dimensions (H x W x D)	13.67 x 5.05 x 11.13 cm
Shipping Weight	2.5 kg

Connections and Interfaces

Port / Terminal Block	Interface Type	Functional Assignment
Ethernet Port	RJ45	Modbus TCP/IP Master (Client) / Slave (Server) connection
Serial Port 1 to 4	Combicon Terminal	Modbus RTU/ASCII Master or Slave (RS-232, RS-422, or RS-485 configuration)
Power Terminal	3-Position Pluggable	V+ (10 to 36 VDC), V- (DC Return), and Earth Ground

Empirical Engineering Insights

Alternative Models & Compatibility

The PLX31-MBTCP-MBS4 serves as a modernized replacement for older legacy gateways. When transitioning configuration profiles from previous-generation ProSoft modules, verify database memory mappings, as the internal database register structures may require offset realignment. Use the ProSoft Configuration Builder (PCB) software for smooth parameter migration.

Application Pitfalls & Engineering Notes

A common issue during multi-port commissioning is Modbus TCP/IP transaction timeouts caused by slower serial-side responses. Ensure that your Modbus TCP master poll timeout matches the longest potential serial round-trip time. When running RS-485 configurations with high slave counts or long cable distances, external 120-ohm termination resistors must be installed at both physical ends of the trunk to prevent signal reflections.

Commissioning & Wiring Tips

The four serial interfaces feature specialized 2500 Vrms digital isolation chips. To maintain this high level of isolation performance, never share common reference or shield lines between different isolated ports or external power sources. For noisy VFD environments, utilize double-shielded twisted-pair (STP) cabling for all serial trunks and tie the cable shields directly to the cabinet ground at a single, centralized point.

Installation Guidelines

CRITICAL WARNING: De-energize all power lines before attempting to install, wire, or remove the gateway module. Touching live electrical terminations can lead to severe equipment damage, electrical shock, or physical injury. Ensure the internal system ground terminal is properly bonded to a low-impedance earth ground path before applying DC power.

Mount the gateway securely to an approved 35 mm DIN rail inside a protective NEMA or IP54 electrical enclosure, allowing at least 2 inches of clearance at the top and bottom for natural convective cooling.

Configure the internal physical serial port jumpers (underneath the front cover) to choose between RS-232, RS-422, or RS-485 modes for each of the four serial ports.

Connect the isolated serial network cables to the corresponding pluggable Combicon terminal blocks, ensuring correct polarity of Transmit (TX) and Receive (RX) lines.

Connect the Ethernet network cable to the RJ45 port and apply nominal 24 VDC power to the power supply terminal block. Monitor the LED diagnostic indicators to confirm successful module initialization.

Key Features:

#ProSoft PLX31 #Protocol Gateways

Can each serial port run on different communication settings?

Yes. Each of the four serial ports on this module is completely independent. You can configure individual baud rates, parity, stop bits, and physical modes (RS-232, RS-422, or RS-485) per port.

How do you set the IP address of this gateway?

The IP address is set using the ProSoft Configuration Builder (PCB) software over Ethernet, or via the ProSoft Discovery Service utility to detect and assign a static IP address to the module on the local network.

What software is needed to map Modbus TCP/IP registers to Modbus Serial?

No programming is required. Drag-and-drop configuration and custom register mapping are fully handled through ProSoft Configuration Builder (PCB), which is free to download.

Is external termination required for the RS-485 serial networks?

Yes. While the serial ports are isolated, they do not include internal software-selectable termination. For long cable lengths or high noise environments, external 120-ohm resistors must be used at the physical ends of the line.

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Returns & Warranty

30-Day Guarantee: Returns accepted for in-stock products in original, factory-sealed packaging.
12-Month Warranty: Every industrial component is backed by our professional technical warranty.

Orders are processed and delivered Monday-Friday (excluding public holidays).

For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .

TECHNICAL SPECIFICATIONS

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ProSoft PLX31-MBTCP-MBS4 Modbus TCP/IP to Modbus Serial 4 Port Gateway