ProSoft PLX31-MBTCP-MBS4 Product Description

PLX31-MBTCP-MBS4 is a 4-port independent Modbus gateway launched by ProSoft, enabling high-speed bidirectional data conversion between Modbus TCP/IP Ethernet and Modbus serial (RTU/ASCII) devices. It is specifically designed for large-scale integration of Modbus serial ports, sensors, and PLCs, supporting DIN rail installation, full electrical isolation, SD card configuration backup, and multi-port parallel polling. ProSoft Technology Inc.

I. Model Interpretation

PLX31: Independent high-performance network series

MBTCP: Modbus TCP/IP protocol side (Ethernet TCP/IP communication)

MBS4: Modbus Serial protocol side, 4 independent serial ports (RS-232/422/485)

Core Positioning: 4-port Modbus serial ports, Modbus TCP multi-client/server, 10,000-byte data cache, 2500V optical isolation, DIN rail, SD card backup, 400 device access, industrial-grade wide temperature range

ProSoft Technology Inc.

II. Core Hardware Specifications

Mechanical and Power Supply

Installation Method: DIN rail standard installation

Power Supply: 10~36 VDC (nominal 24 VDC), 300 mA @ 24 VDC

Size: 13.67 × 5.05 × 11.13 cm

Weight: Approximately 0.22 kg

Shell: IP20 protection, metal structure, no fan design

Ethernet Interface (Modbus TCP/IP)

Ports: 1 × 10/100 M RJ45, full / half duplex, auto crossover

Isolation: 1500 Vrms electrical isolation (IEC 60950)

Connection Capacity: Up to 20 concurrent connections (clients + servers)

Client Mode: Active connection to 32 Modbus TCP servers

Server Mode: Respond to 32 Modbus TCP client requests

Serial Interface (Modbus Serial, 4 ports)

Ports: 4 × Independent RS-232/422/485 (software configurable)

Isolation: 2500 Vrms optical isolation (UL 1577)

Protocol: Modbus RTU, Modbus ASCII

Baud Rate: 1200 ~ 115200 bps

ProSoft Technology Inc. Mode: Each port is independently configured as a Modbus master station or slave station. ProSoft Technology Inc

Master station capabilities: Each port supports 100 user-defined Modbus commands, totaling 400 commands. ProSoft Technology Inc

Slave station address: 1 - 247. ProSoft Technology Inc

Data and storage

Internal database: 10,000 × 16-bit words (bidirectional data exchange area). ProSoft Technology Inc

Configuration storage: Built-in Flash + SD card slot (configuration backup / restoration). ProSoft Technology Inc

LED indication: PWR, CFG, ERR, FLT, NS, MS, Link/Activity, 4×COM (RX/TX) status. ProSoft Technology Inc

Environment and certification

Operating temperature: -25°C ~ +70°C

Storage temperature: -40°C ~ +80°C

Humidity: 5% ~ 95% (no condensation)

Shock resistance: 5G @ 10~150 Hz

Impact resistance: 15G (operation), 30G (non-operation)

Certifications: CE, UL/cUL, RoHS, DNV, ABS

Optional: Corrosion-resistant coating (suitable for high humidity, dust, and corrosive environments). ProSoft Technology Inc

III. Core functions and working principle

1. Protocol conversion mechanism

Bidirectional data forwarding: Modbus TCP/IP ↔ Modbus Serial automatic mapping. ProSoft Technology Inc

Data buffer: 10,000 words shared memory, achieving protocol decoupling and high-speed exchange. ProSoft Technology Inc

Independent control of 4 ports: Each port's parameters, mode, and instruction list are completely independent. ProSoft Technology Inc

Master/Slave flexible configuration

Master station mode: Active polling of Modbus instruments, inverters, PLCs. ProSoft Technology Inc

Slave station mode: As a Modbus slave station accessed by third-party SCADA/PLC. ProSoft Technology Inc

2. Functions on the Modbus TCP/IP side

Multiple clients/servers: Supports 20 concurrent connections. ProSoft Technology Inc

Function codes supported: 1/2/3/4/5/6/15/16/22, etc. standard Modbus function codes. ProSoft Technology Inc

Data mapping: Free mapping of Modbus TCP addresses ↔ internal database. ProSoft Technology Inc

Timeout retry: Automatic error handling, fault node isolation. ProSoft Technology Inc

Floating point support: Enron, Daniel floating point protocol. ProSoft Technology Inc

3. Functions on the Modbus Serial side (master station)

400 command queues: Supports batch reading and writing, up to 125 registers/commands. ProSoft Technology Inc Polling Scheduling: Periodic / Triggered / Conditional Polling, Optimizing Bus Load. ProSoft Technology Inc

Error Handling: Automatic Retry, Timeout, Fault Node Isolation. ProSoft Technology Inc

Address Mapping: Modbus Address ↔ Internal Database Free Mapping. ProSoft Technology Inc

Multi-Port Parallel: 4 Serial Ports Polling Independently at the Same Time, Improving System Response Speed. ProSoft Technology Inc

4. Reliability and Maintenance

Full Electrical Isolation: Ethernet, Serial Port, Power Supply Three-Port Isolation, Anti-interference, Lightning Protection. ProSoft Technology Inc

SD Card Backup: Configuration Quick Cloning, Fault Quick Recovery. ProSoft Technology Inc

Web Diagnosis: Built-in Web Server, Remote Status Monitoring, Log Viewing. ProSoft Technology Inc

ProSoft Discovery Service: Cross-Subnet Discovery Module, IP Modification. ProSoft Technology Inc

Security Switch: Hardware Configuration Lock, Preventing Accidental Modification (v1.04+). ProSoft Technology Inc

Four. Core Advantages

1. Industrial-grade Stable and Reliable

Wide Temperature, Isolation, No Fan, Adapted to Extreme Industrial Sites

2500V Photoelectric Isolation, Completely Solving Ground Potential Difference, Strong Electromagnetic Interference. ProSoft Technology Inc

Independent Gateway: Does Not Occupy PLC Slot, Does Not Increase System Load. ProSoft Technology Inc

2. 4 Port High-Density Integration

4 Independent Serial Ports, Each Port RS-232/422/485 Switchable. ProSoft Technology Inc

Single Gateway Connects 400 Modbus Devices, Significantly Reduces Gateway Quantity. ProSoft Technology Inc

400 Instructions, 10,000 Bytes Data Area, Meeting Large-scale Systems. ProSoft Technology Inc

Multi-Port Parallel Polling, System Response Speed Improved by 4 Times. ProSoft Technology Inc

3. High-Speed Ethernet Interconnection

Modbus TCP Multiple Clients / Servers, Single Gateway Connects 32 Devices. ProSoft Technology Inc

10/100M Adaptive, High-Speed Data Exchange. ProSoft Technology Inc

Automatic Cross-over, Simplifying Network Wiring. ProSoft Technology Inc

4. Easy to Use and Maintain

DIN Rail, Plug-and-Play

SD Card Configuration Backup, Batch Deployment, Quick Replacement. ProSoft Technology Inc

LED + Web Dual Diagnosis, Precise Fault Location. ProSoft Technology Inc

Cross-Subnet Configuration Tool, Simplifying Network Deployment. ProSoft Technology Inc

Five. Typical Application Scenarios

Modbus TCP Network Large-scale Access to Modbus Serial Port Instruments (Flowmeters, Pressure Gauges, Sensors). ProSoft Technology Inc Multiple Modbus frequency converters and servo controllers on the production line are centrally controlled by ProSoft Technology Inc.

The old Modbus serial system in the factory has been upgraded to connect to the Modbus TCP network. ProSoft Technology Inc.

The SCADA system monitors distributed Modbus RTU devices through Modbus TCP.

Interconnection of multiple manufacturer devices (Modbus TCP ↔ Modbus serial protocol devices). ProSoft Technology Inc.

Remote I/O system: 4 serial ports cover devices in multiple areas, reducing wiring costs. ProSoft Technology Inc.

Six. Summary

PLX31-MBTCP-MBS4 is an industrial-grade standard gateway for large-scale interconnection of Modbus TCP/IP and Modbus serial devices. With 4 independent RS-232/422/485 ports, single gateway for 400 Modbus devices, Modbus TCP multi-client/server, 10,000-byte data cache, 2500V full optoelectronic isolation, SD card configuration backup, and wide-temperature industrial-grade design as core advantages, it perfectly realizes seamless data connection between Modbus TCP network and various Modbus serial devices. It is a highly reliable and high-performance solution for high-density protocol conversion in industrial sites, upgrading of old systems, and integration of multiple devices, significantly reducing system costs and complexity. ProSoft Technology Inc.