Modalo - Modbus Data Logger

A robust Windows-based Modbus data acquisition and logging system designed for industrial applications, with support for multiple devices, flexible configuration, and comprehensive error handling.

Overview

Modalo is a professional-grade Modbus polling application that enables real-time data collection from multiple Modbus devices (RTU). It provides flexible configuration management, JSON-based register mapping, and detailed logging capabilities with advanced error handling.

Features

Core Functionality

• Multi-Device Polling: Poll and collect data from multiple Modbus devices simultaneously
• Flexible Configuration: Editable configuration files for easy portability and deployment
• Register Support: Full support for U16, U32, and IEEE-float32 register types
• Endianness Control: Support for both big-endian and little-endian register formats
• JSON Configuration: Parse register maps and settings from JSON files (beta)
• Backward Compatibility: Maintains compatibility with older configuration and map file formats

Data Management

• Plant Code Tracking: Include plant identification in configuration and log filenames
• UTC Time Format: All timestamps use UTC format with Z terminator for standardized logging
• Device Identification: Uses Slave ID for unique device identification
• Flexible Logging: Output data to console or log files with configurable verbosity

Reliability & Security

• Error Handling: Detailed error handling and reporting through dedicated error module
• Security: Preprocessor directives to hide non-API functions from DLL export (mitigates DLL injection attacks)
• Verbose Mode: Debug mode for troubleshooting and detailed operation tracking
• Standard Windows Runtime: Compiled with standard UCRT for maximum compatibility

Platform Support

• Windows 9+: Requires Windows 9 or later
• DLL Architecture: Core Modbus functionality encapsulated in DLL for version control and stability

System Requirements

• OS: Windows 9 or later
• Runtime: Standard UCRT (Universal C Runtime) library
• Architecture: x86/x64

Installation

1. Download the main branch
2. Extract files to your desired installation directory
3. Configure the application using the config file (see Configuration section)
4. Compile and run the executable. Or download the release from bin.

Configuration

Config File Structure

The application uses an editable configuration file to specify:
- Device connection parameters (IP, port, or serial port)
- Polling intervals
- Plant code identifier
- Register map file path
- Output log file path
- Verbosity settings

Register Map (map.json)

Define your register mappings in JSON format:

{
  "registers": [
    {
      "name": "voltage",
      "address": 100,
      "type": "IEEE-float32",
      "endian": "big"
    },
    {
      "name": "current",
      "address": 102,
      "type": "U16",
      "endian": "little"
    }
  ]
}

Supported Register Types:
- U16: 16-bit unsigned integer
- U32: 32-bit unsigned integer
- IEEE-float32: 32-bit floating point

Usage

Basic Operation

.\bin\modalo.exe 

Output Files

• Log Files: Located in configured directory with naming convention: PLANTCODE_YYYY-MM-DD.log
• Console Output: Real-time polling status and error messages (if verbose mode enabled)

Verbose Mode

Enable debug logging by setting verbose mode in configuration:
- Detailed function call tracing
- Register read/write debugging
- Connection status information

Version History

V1.0

• Support for solis invertV1.1.
• Added editable config file for portability
• Added parsing of config file
• Added support for U16 and U32 registers.

V1.2

• Added support for detailed error handling & error module
• Added support for parsing json file (beta)
• Added support for other endien (big/little) register
• Added support for reading register map from json (beta)
• Shifted core functionality of modbus to dll file for version control.

V1.3

• Bug fix while reading little endien register
• Bug fix while parsing incomplete config file
• Changed time format to UTC with Z terminator
• Bug fix in file interval - Active throughout the valid minute

V1.4

• Added plant code to config file.
• Added plant code to logfileName
• Cleaned and optimised token validation function for json parser
• Bug fix while printing parity to console window
• Recombiled for standard UCRT windows runtime library.
• Removed support for windows 8 and below.

V2.0

• Added functionality for polling multiple devices
• Added preprocessor directives for hidding nonAPI function from dll export (demotivate dll injection attack)
• Removed asset ID from config file and use slave ID instead as device Identification.

V2.1

• Added verbose mode by using debug mode in modbus library.
• Diverted stderr to logfile.
• Modified printModaloConfig, printModalo & printOnly function to print to given FILE DESCRIPTOR
• Recombiled libmodbus.dll with DLL_EXPORT defined to remove unused functions from exporting.
• Add float register type to map.json (U32,U16, IEEE-float32) maintaining backward compatibility with older versions of config and map files

VX.X (pending)

• WINAPI main for hiding console window and using window UI
• UI editor for configuration files and map files

Supported Devices

Modalo has been tested and verified with:
- Solis Inverters (V1.1+)
- ABB Inverters
-
- Generic Modbus RTU devices
- Generic Modbus TCP devices

Architecture

Components

1. Main Application: Handles polling logic and file I/O
2. libmodbus.dll: Core Modbus protocol implementation with hidden non-API exports
3. Configuration Parser: Reads and validates config files
4. JSON Parser: Processes register map definitions
5. Error Handler: Centralized error logging and reporting

DLL Design

• Minimized export surface to prevent injection attacks
• Version-controlled Modbus implementation
• Optimized for standard Windows runtime environments

Troubleshooting

Common Issues

Connection Timeout
- Verify device IP/port or serial port settings
- Check firewall settings for TCP connections
- Ensure Slave ID matches device configuration

Register Read Errors
- Verify register address matches device documentation
- Check endianness setting matches device format
- Confirm register type (U16/U32/IEEE-float32) is correct

Incomplete Config File
- Validate JSON syntax in configuration files
- Ensure all required fields are present
- Check file encoding (UTF-8 recommended)

Parity Errors
- For RTU connections, verify parity setting matches device
- Common settings: None, Even, or Odd
- Recompile from source if using non-standard parity modes

Building from Source

The project includes source for:
- Main application (C/C++)
- libmodbus.dll wrapper (C)
- Configuration and JSON parsers

Build with Visual Studio 2019+ or compatible compiler with UCRT support.

License

MIT License

Contributing

Contributions are welcome! Please ensure compatibility with:
- Windows 9+
- Standard UCRT runtime
- Existing configuration file format (for backward compatibility)

Support

For issues, questions, or feature requests, please:
1. Check the Troubleshooting section
2. Enable verbose mode for detailed debugging information
3. Review log files in the configured output directory
4. Contact the development team with:
- Windows version
- Device model and Modbus version
- Configuration and map files (sanitized)
- Relevant log excerpts

Roadmap

• Near Term: UI-based configuration editor
• Future: Enhanced Modbus TCP security (Modbus/TCP over SSL)
• Optimization: Performance improvements for high-frequency polling

Current Version: 2.1
Last Updated: May 5, 2026
Platform: Windows 9+