Modbus OPC server



MasterOPC Universal Modbus Server is an OPC server for applications that communicate using the popular industrial protocol Modbus. The product supports the following Modbus modifications:

  • Modbus RTU (including SLAVE)
  • Modbus ASCII
  • Modbus TCP/IP (including SLAVE)
  • Modbus over TCP (support of Ethernet-COM converters)

MasterOPC Universal Modbus OPC Server has the following distinctive features:

  • Built-in textual programming editor that essentially expands the product functionality
  • Group operations on variables and Import of previously configured OPC tree device components and variables which grant a fast and easy way to create analogous new device configurations
  • Redundancy: Increased Polling Reliability
  • MQTT: Integration with IoT Devices and Cloud Services
  • MODBC: Databases Connection
  • IEC 60870-5-104: IEC 60870-5-104 Protocol Server

Available Variants

  • Small (MPS-OPC-Modbus-S) – OPC-server for Modbus RTU/TCP/ASCII 2,500 tags
  • Medium (MPS-OPC-Modbus-M) – OPC-server for Modbus RTU/TCP/ASCII 2,501 – 20,000 tags including ODBC
  • Large (MPS-OPC-Modbus-H) – OPC-server for Modbus RTU/TCP/ASCII 20,001 – 200,000 tags including ODBC/MQTT/IEC60870-5-104 connector


MasterOPC Universal Modbus Server is an OPC server for Modbus RTU/ASCII/TCP industrial applications. The Modbus OPC server provides two OPC interfaces: DA (Data Access, processed data) and HDA (Historical Data Access, archived data). To organize the storage of archived variables data MasterOPC uses the built-in SQL server.

The built-in programming editor (Lua Script) provides additional processing on data received from external devices as well as processing of data being sent to external devices. Processing variables via scripts using the built-in programming language is equaly essential for other important purposes. Using the scripting utility you can:

  • Develop new drivers (drivers for Modbus based protocols and drivers for protocols based on any other standards)
  • Develop various signal simulators
  • Calculate parameters via an indirect way or without interfering with the devices calculation algorithms
  • Operate with the quality parameters of tags

Scripts can be applied at any level in the OPC tree (communication nodes, devices, sub-devices or tags). The built-in editor provides other standard services such as keyword highlight, convenient work with tags or libraries, etc.

The server by default supports other typical operations on tags such as: automatic type casting, conversion to real measurement units, byte swapping, bit extraction, etc.

MasterOPC supports communication over GSM or other modem connections. This allows it to be used in supervisory control and/or data acquisition systems. MasterOPC can operate as well as a TCP server; this allows an effective use of MasterOPC together with 3G/4G/5G gateways without using static IP addressing mode. For diagnostic purposes, during run-time, MasterOPC logs and displays data transfer detailed events from driver or from script generators as user friendly messages and as Modbus protocol data units messages which help users of different qualification levels to track data transfer events.


Basic features of MasterOPC Universal Modbus OPC Server:

  • Communication with Modbus RTU/ASCII network over a dedicated line via serial interface (RS-232 or RS-485)
  • Communication via TCP/IP, including Modbus TCP
  • Communication in the “Modbus over TCP” mode intended to support interaction via “Ethernet-RS-232/422/485” converters
  • TCP Server mode. In this mode, the OPC server waits for incoming TCP connections at the specified port and establishes the connection. In addition, this mode allows communication with 4G/5G gateways without static IP addresses assignment.
  • Communication with devices via Modbus RTU/ASCII/TCP in “Slave” mode
  • Communication with devices via GSM modem and sending of SMS messages
  • Monitoring values of variables


Predominant MasterOPC Universal Modbus OPC Server features:

  • Scaling of variables (variable value range is required)
  • Group editing of tags properties
  • Import of tags from CSV files, using built-in wizard
  • Arbitrary byte swapping (with 8 bytes of maximum word length)
  • Extraction of individual bits in tag values
  • Automatic type casting
  • Support bool, int16, uint16, int32, uint32, float, double, string data types
  • Detailed diagnostic messages logging
  • Communication quality tracing
  • Support Modbus function 20 (0x14 – Read File Record)
  • Generate any Modbus request
  • Flexible control of group requests
  • Simultaneous extraordinary reading after writing values while controlling
  • Tracing data transfer with a device
  • Archiving tags; transferring archives via OPC HDA
  • Adaptation with DCON or other protocols with an effort of writing additional scripts


Features of the built-in scripting language (Lua Script)

  • Built-in editor with keyword highlighting which provides a convenient way of working with tags and function libraries
  • Expand or fold lines of the code (the script) in the editor
  • Support development of OPC DA/HDA servers for other communication protocols (The software package includes Scripts that provide communication with ICPDAS modules via DCON protocols)
  • Processing of a variable value after reading or before writing
  • Operations on quality tags
  • Development of signal simulators (using a script)
  • Data archiving to SQLite databases


Redundancy: Increased Polling Reliability

Redundancy of communication channels

Redundancy allows you to create highly reliable connections with controllers and equipment.

Feature highlights:

  • Up to 4 TCP channels.
  • Automatic failover to a standby channel upon detection of communication failure.
  • Manual failover to a standby channel.


MQTT: Integration with IoT Devices and Cloud Services

MQTT protocol support.

MQTT protocol is designed for communication with IoT devices (Internet of Things Devices) and integration with cloud services (Microsoft Azure, Amazon Web Services, etc.). This functionality allows you to send and receive data from OPC servers in various cloud applications.

Feature highlights:

  • Transfer values of any server tags together with timestamps and quality tags.
  • Receive values from other MQTT devices and write them to tags.
  • Intuitive flexible configuration of MQTT telegrams with receipt acknowledgement, as well as flexible configuration of message format.
  • Track  MQTT broker connection state  with optional automatic reconnection on failure.


ODBC: Databases Connection

ODBC technology support.

ODBC technology provides integration with various DBMS (MS SQL, Oracle, MySQL, PostgreSQL, etc.). Built-in script editor exposes additional functionality to process data returned by an arbitrary SQL query. This makes integration of OPC server with applications that do not support OPC natively such as MES, ERP and BI systems a breeze.

Feature highlights:

  • Support for all ODBC-enabled database engines.
  • Custom methods listed in ODBC section of the script editor enable query execution, connection and transaction management.
  • Read HDA archive for arbitrary tags and store it in the database using a custom method “ReadHDAFromTag.”
  • Detailed examples of ODBC operations in the help system.


IEC 60870-5-104 Server

IEC 60870-5-104 is an industry protocol mainly used in the Energy and Oil & Gas industries. Our OPC server supports IEC104 mode. This mode allows for an OPC server adapter from Modbus to IEC104 protocol while supporting other interfaces (OPC DA, UA, ODBC and MQTT).

Feature highlights:

  • Set connection port and ASDU address
  • Individual tag configuration (visibility via the IEC104 protocol, address, value transfer method, read-only, etc.)