Modbus Tester

A Modbus master/simulator desktop application for testing Modbus RTU (RS-485/RS-232) and Modbus TCP/IP connections.

Features

• Modbus RTU (master) via RS-485/RS-232
• Modbus TCP (client/master)
• Multiple parallel sessions with multi-view support
• Read coils, discrete inputs, input registers and holding registers
• Write values via dedicated write dialog (function codes 05, 06, 0F, 10)
• Integrated Modbus Simulator - Start TCP/RTU simulators directly from the app
• Device Scanner - Automatically discover Modbus devices on RTU bus or TCP/IP network
  • RTU Scanner - Scan serial bus for device IDs and active registers
  • TCP Scanner - Scan network IP ranges and ports for Modbus TCP devices
  • Export to PDF - Save device information as PDF for documentation
  • Import Connection/Session - Right-click on found devices to automatically import them
• Multi-view - View multiple sessions side-by-side in groups
• Graph - Data Visualization - Real-time time-series graphs of Modbus data
  • Select rows to graph - Choose one or more data points from the table to visualize
  • Real-time updates - Graph automatically updates with new poll results
  • Hover tooltip - See exact time and value by hovering over data points
  • Adjustable axes - Auto-scale or manual min/max for both time and value axes
  • Update frequency control - Adjust how often the graph refreshes (1-100 polls)
  • Multiple series - Each selected row appears as a separate colored line
  • Non-modal window - Use the main window while viewing graphs
• Tag Management - Define custom tags with data types, scaling, and units
• Device Templates & Tag Library - Reusable tag sets for standard equipment (VAV boxes, pumps, VFDs, etc.)
  • Save tags as template - Create reusable templates from session tags
  • Load from template - Quickly apply standard tag sets to sessions
  • CSV/Excel Import/Export - Import register overviews from suppliers or export tag lists for BMS projects
• Frame/Trace Analyzer - Advanced communication analysis and diagnostics
  • Frame log table - View all TX/RX telegrams with timestamps, direction, slave ID, function codes, and results
  • Detailed frame information - Decoded info, raw hex, error descriptions
  • Statistics - Request/response counts, timeouts per slave, average response times
  • Auto-diagnostics - Automatic detection of common issues (timeouts, ID conflicts, exceptions)
  • Filtering - Filter by direction, status, slave ID, function code
• Snapshot & Compare - Capture and compare installation states
  • Take snapshots - Capture current state of single session or all sessions
  • Manage snapshots - View, compare, delete, and export snapshots
  • Compare snapshots - Side-by-side comparison of two snapshots with diff highlighting
  • Export comparisons - Export diff results to CSV for documentation
• Data Types Support - UINT16, INT16, UINT32, INT32 (DINT), FLOAT32, BOOL
• HEX Display - View hexadecimal representation of all values
• Dark Theme - Modern dark interface for reduced eye strain
• Resizable Panels - Adjustable splitter between Connections and Sessions
• Auto-save UI Settings - Window position and panel sizes are saved automatically
• Comprehensive debugging: hexdump, timestamps, log, status codes
• Real-time data display in tables with simultaneous view of raw addresses and tags
• Write operations via "Skriv værdi..." button with support for single and multiple writes
• Project management - Save and reopen configurations (including multi-view setup)

Installation

pip install -r requirements.txt

Running

Main Application

python src/main.py

Modbus Simulator (for testing)

Recommended: Use the integrated simulator in the app via Advanced → Modbus Simulator...

Alternatively, you can run the simulator from the command line:

TCP Simulator:

python src/simulator/modbus_simulator.py --type tcp --host 127.0.0.1 --port 5020

RTU Simulator:

python src/simulator/modbus_simulator.py --type rtu --serial-port COM10 --baudrate 9600

Or use the simple script:

python start_rtu_simulator.py

This starts the RTU simulator on COM10 at 9600 baud.

The simulator has the following test data:

• Holding registers (0-9): 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000
• Holding registers (20-31): DINT (INT32) test values (1,000,000, -500,000, MAX/MIN INT32, etc.)
• Holding registers (40-49): Dedicated write addresses (initialized to 0)
• Input registers (0-9): 50, 150, 250, 350, 450, 550, 650, 750, 850, 950
• Input registers (20-31): DINT (INT32) test values
• Coils (0-9): True, False, True, False, True, False, True, False, True, False
• Coils (20-29): Dedicated write addresses (initialized to False)
• Discrete inputs (0-9): False, True, False, True, False, True, False, True, False, True

Connection example:

1. Start the application: python src/main.py
2. Start the simulator via Advanced → Modbus Simulator... → Start TCP Simulator (port 5020)
3. Create a new TCP connection with:
   • Host: 127.0.0.1
   • Port: 5020
   • Slave ID: 1
4. Create a session with:
   • Function code: 03 (Read Holding Registers)
   • Start address: 0
   • Quantity: 10
5. Start polling to see the data
6. (Optional) Click "Write Value..." to write values to addresses 40-49

Graph:

• Select one or more rows in the data table
• Click "Show Graph..." button in the session tab
• View real-time time-series visualization of your data
• Hover over the graph to see exact time and value
• Adjust X/Y axis settings and update frequency in the control panel
• Graph window is non-modal - use main window while viewing graphs

Multi-view:

• Create groups via View → Manage Multi-view...
• Activate multi-view via View → Multi-view
• View multiple sessions side-by-side
• Multi-view configuration is saved with projects

Device Scanner:

• Go to Connection → Device Scanner...
• RTU Scanner Tab:
  • Select COM port and configure serial settings (baudrate, parity, etc.)
  • Set device ID range to scan (default: 1-247)
  • Click "Start Scan" to automatically discover Modbus devices on serial bus
• TCP Scanner Tab:
  • Enter IP range (e.g., "192.168.1.1-254" or "192.168.1.0/24" for CIDR notation)
  • Enter ports to scan (e.g., "502" or "502,5020" for multiple ports)
  • Set device ID range to scan (default: 1-247)
  • Click "Start Scan" to automatically discover Modbus TCP devices on network
• Features:
  • Results show available register types and active addresses
  • Save as PDF: Click "Save as PDF" button to export device information
  • Import Connection: Right-click on found device → "Import Connection" to create connection profile
  • Import Session: Right-click on found device → "Import Session" to create connection and session automatically
  • Note: Only addresses with active values are shown (non-zero for registers, True for coils)

Tag Management:

• Click "Manage Tags..." in a session tab
• Define custom tags with names, data types, byte order, scaling, and units
• Supports: UINT16, INT16, UINT32, INT32 (DINT), FLOAT32, BOOL
• Tags must match the session's function code (address_type)
• Tags are displayed below raw addresses in the data table, separated by "--- Tags ---" line
• You can see both raw addresses and decoded tags simultaneously

Device Templates & Tag Library:

• Go to Session → Device Templates... to manage template library
• Save tags as template: In tag management dialog, click "Save tags as template..." to create a reusable template
• Load from template: In tag management dialog, click "Load from template..." to quickly apply standard tag sets
• Import/Export: Import CSV/Excel files with register overviews or export templates for use in other systems
• Templates are perfect for standard equipment (VAV boxes, pumps, VFDs, ventilation units, etc.)

Frame/Trace Analyzer:

• Go to Advanced → Frame Analyzer... to open the analyzer
• View all Modbus communication frames in a table with:
  • Timestamp, direction (TX/RX), slave ID, function code, address range, result, response time
• Click on a frame to see detailed information:
  • Raw hex data, decoded info, error descriptions
• Statistics tab: View aggregated statistics (total requests, timeouts per slave, average response times)
• Diagnostics tab: See automatic findings (e.g., "Many timeouts on Slave 3 - check cable/ID/baudrate")
• Use filters to focus on specific issues (errors only, specific slave ID, function code, etc.)

Snapshots & Compare:

• Go to Snapshots → Take Snapshot... to capture current state
• Choose scope: Current session or all sessions
• Add a name and optional note for the snapshot
• Go to Snapshots → Manage Snapshots... to:
  • View all snapshots with details
  • Compare two snapshots (select 2 snapshots with Ctrl+click, then click "Compare...")
  • Export snapshots or comparisons to CSV
  • Delete snapshots
• Compare view: See side-by-side comparison with:
  • Changed values highlighted
  • Numeric differences and percentages
  • Filter to show only changed values
  • Export diff to CSV for documentation

Write Operations:

• Click "Write Value..." button in session tab
• Select write function code (05, 06, 0F, or 10)
• Enter address and value(s)
• For multiple writes: Enter comma-separated values or one large value (auto-split for multiple registers)
• Data automatically refreshes after successful write
• Function code dropdown only shows read functions (01-04) - write is done via the write button

User Interface:

• Dark theme for reduced eye strain
• Resizable panels - drag the splitter between Connections and Sessions
• Window position and panel sizes are automatically saved
• HEX column shows hexadecimal representation of values
• Data table shows raw addresses first, then tags (separated by "--- Tags ---" line)

Build Executable (.exe)

To build a standalone .exe file:

# Install PyInstaller (if not already installed)
pip install pyinstaller

# Build executable
python build_exe.py

Or use the batch file:

build_exe.bat

The executable will be placed in dist/ModbusTester.exe

Notes:

• The executable is standalone and does not require Python installation
• First build may take a few minutes
• The executable will be approximately 50-100 MB (includes Python runtime and all dependencies)

Technology Stack

• Python 3.10+
• PyQt6 (GUI)
• pymodbus (Modbus protocol)
• pyserial (Serial communication)
• PyInstaller (for building .exe)

---

Modbus Tester

En Modbus master/simulator desktop-applikation til test af Modbus RTU (RS-485/RS-232) og Modbus TCP/IP forbindelser.

Funktioner

• Modbus RTU (master) via RS-485/RS-232
• Modbus TCP (client/master)
• Flere parallelle sessions med multi-view support
• Læs/skriv coils, discrete inputs, input registers og holding registers
• Integreret Modbus Simulator - Start TCP/RTU simulatoren direkte fra appen
• Device Scanner - Find automatisk Modbus enheder på RTU bus eller TCP/IP netværk
  • RTU Scanner - Scan seriel bus for device IDs og aktive registre
  • TCP Scanner - Scan netværk IP ranges og porte for Modbus TCP enheder
  • Eksporter til PDF - Gem device information som PDF til dokumentation
  • Importer Connection/Session - Højreklik på fundne enheder for automatisk at importere dem
• Multi-view - Se flere sessions side om side i grupper
• Tag Management - Definer brugerdefinerede tags med datatyper, skalering og enheder
• Datatyper Support - UINT16, INT16, UINT32, INT32 (DINT), FLOAT32, BOOL
• HEX Visning - Se hexadecimal repræsentation af alle værdier
• Mørkt Tema - Moderne mørkt interface for mindre anstrengelse
• Justerbare Paneler - Justerbar splitter mellem Connections og Sessions
• Auto-gem UI Indstillinger - Vindue position og panel størrelser gemmes automatisk
• Omfattende fejlsøgning: hexdump, tidsstempler, log, statuskoder
• Real-time data visning i tabeller
• Manuel write operationer
• Projekt management - Gem og genåbn konfigurationer (inkl. multi-view opsætning)

Installation

pip install -r requirements.txt

Kørsel

Hovedapplikation

python src/main.py

Modbus Simulator (til test)

Anbefalet: Brug den integrerede simulator i appen via Vis → Modbus Simulator...

Alternativt kan du køre simulatoren fra kommandolinjen:

TCP Simulator:

python src/simulator/modbus_simulator.py --type tcp --host 127.0.0.1 --port 5020

RTU Simulator:

python src/simulator/modbus_simulator.py --type rtu --serial-port COM10 --baudrate 9600

Eller brug det simple script:

python start_rtu_simulator.py

Dette starter RTU simulatoren på COM10 med 9600 baud.

Simulatoren har følgende testdata:

• Holding registers (0-9): 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000
• Input registers (0-9): 50, 150, 250, 350, 450, 550, 650, 750, 850, 950
• Coils (0-9): True, False, True, False, True, False, True, False, True, False
• Discrete inputs (0-9): False, True, False, True, False, True, False, True, False, True

Eksempel på forbindelse:

1. Start applikationen: python src/main.py
2. Start simulatoren via Vis → Modbus Simulator... → Start TCP Simulator (port 5020)
3. Opret en ny TCP forbindelse med:
   • Host: 127.0.0.1
   • Port: 5020
   • Slave ID: 1
4. Opret en session med:
   • Function code: 03 (Read Holding Registers)
   • Start address: 0
   • Quantity: 10
5. Start polling for at se dataene

Multi-view:

• Opret grupper via Vis → Manage Multi-view...
• Aktiver multi-view via Vis → Multi-view
• Se flere sessions side om side
• Multi-view konfiguration gemmes med projekter

Device Scanner:

• Gå til Connection → Device Scanner...
• RTU Scanner Tab:
  • Vælg COM port og konfigurer serielle indstillinger (baudrate, parity, etc.)
  • Sæt device ID range til at scanne (standard: 1-247)
  • Klik "Start Scan" for automatisk at finde Modbus enheder på seriel bus
• TCP Scanner Tab:
  • Indtast IP range (f.eks. "192.168.1.1-254" eller "192.168.1.0/24" for CIDR notation)
  • Indtast porte til at scanne (f.eks. "502" eller "502,5020" for flere porte)
  • Sæt device ID range til at scanne (standard: 1-247)
  • Klik "Start Scan" for automatisk at finde Modbus TCP enheder på netværket
• Funktioner:
  • Resultater viser tilgængelige register typer og aktive adresser
  • Gem som PDF: Klik "Save as PDF" knap for at eksportere device information
  • Importer Connection: Højreklik på funden enhed → "Import Connection" for at oprette connection profile
  • Importer Session: Højreklik på funden enhed → "Import Session" for at oprette connection og session automatisk
  • Bemærk: Kun adresser med aktive værdier vises (non-zero for registre, True for coils)

Tag Management:

• Klik "Manage Tags..." i en session tab
• Definer brugerdefinerede tags med navne, datatyper, byte order, skalering og enheder
• Understøtter: UINT16, INT16, UINT32, INT32 (DINT), FLOAT32, BOOL
• Tags skal matche sessionens function code (address_type)

Device Templates & Tag-bibliotek:

• Gå til Session → Device Templates... for at administrere template-biblioteket
• Gem tags som template: I tag management dialog, klik "Save tags as template..." for at oprette en genbrugelig template
• Indlæs fra template: I tag management dialog, klik "Load from template..." for hurtigt at anvende standard tag-sæt
• Import/Eksport: Importer CSV/Excel filer med registeroversigter eller eksporter templates til brug i andre systemer
• Templates er perfekte til standardudstyr (VAV-bokse, pumper, VFD, ventilationsaggregater, osv.)

Frame/Trace Analyzer:

• Gå til Vis → Frame Analyzer... for at åbne analyseren
• Se alle Modbus kommunikationsframes i en tabel med:
  • Tidsstempel, retning (TX/RX), slave ID, function code, adresseområde, resultat, responstid
• Klik på en frame for at se detaljerede informationer:
  • Rå hex data, dekodet info, fejlbeskrivelser
• Statistics fanen: Se aggregerede statistikker (total requests, timeouts per slave, gennemsnitlig responstid)
• Diagnostics fanen: Se automatiske findings (f.eks. "Mange timeouts på Slave 3 - tjek kabel/ID/baudrate")
• Brug filtre til at fokusere på specifikke problemer (kun fejl, specifik slave ID, function code, osv.)

Snapshots & Compare:

• Gå til Snapshots → Take Snapshot... for at fange nuværende tilstand
• Vælg scope: Aktuel session eller alle sessions
• Tilføj et navn og valgfri note til snapshot
• Gå til Snapshots → Manage Snapshots... for at:
  • Se alle snapshots med detaljer
  • Sammenligne to snapshots (vælg 2 snapshots med Ctrl+klik, klik derefter "Compare...")
  • Eksportere snapshots eller sammenligninger til CSV
  • Slette snapshots
• Compare view: Se side-om-side sammenligning med:
  • Ændrede værdier fremhævet
  • Numeriske forskelle og procenter
  • Filter for kun at vise ændrede værdier
  • Eksport diff til CSV til dokumentation

Brugergrænseflade:

• Mørkt tema for mindre anstrengelse
• Justerbare paneler - træk splitteren mellem Connections og Sessions
• Vindue position og panel størrelser gemmes automatisk
• HEX kolonne viser hexadecimal repræsentation af værdier

Byg Executable (.exe)

For at bygge en standalone .exe fil:

# Installer PyInstaller (hvis ikke allerede installeret)
pip install pyinstaller

# Byg executable
python build_exe.py

Eller brug batch filen:

build_exe.bat

Executablen vil blive placeret i dist/ModbusTester.exe

Noter:

• Executablen er standalone og kræver ikke Python installation
• Første build kan tage et par minutter
• Executablen vil være ca. 50-100 MB (inkluderer Python runtime og alle dependencies)

Teknologistack

• Python 3.10+
• PyQt6 (GUI)
• pymodbus (Modbus protokol)
• pyserial (Seriel kommunikation)
• PyInstaller (til at bygge .exe)