Your first logging session

This tutorial walks you through a complete ModbusScope session from a fresh installation to a saved CSV file. You will connect to a Modbus TCP device, add three registers, log data, and export it.

What you need:

  • ModbusScope installed on your computer (download)

  • A Modbus TCP device reachable on your network (this tutorial uses 192.168.1.10, port 502, slave ID 1)

  • Three holding registers at addresses 40001, 40002, 40003

If your device uses different values, substitute them at each step.

Step 1 — Add a connection

  1. Open ModbusScope.

  2. Go to Settings > Connection.

  3. Set Protocol to TCP.

  4. Set IP address to 192.168.1.10.

  5. Set Port to 502.

  6. Leave Timeout at the default.

  7. Click OK.

Step 2 — Add a device

  1. Go to Settings > Device.

  2. Click Add device.

  3. Set Name to My device.

  4. Set Connection ID to 1 (the connection you just created).

  5. Set Slave ID to 1 (the Modbus slave ID of the device).

  6. Click OK.

Step 3 — Add registers

  1. Click Register Settings in the toolbar.

  2. Click Add to add a new row.

  3. In the Expression column, type ${40001}. Set Name to Register 1.

  4. Add a second row: expression ${40002}, name Register 2.

  5. Add a third row: expression ${40003}, name Register 3.

  6. Click OK.

Step 4 — Start logging

  1. Click Start Logging.

The graph starts updating in real time. Each register appears as a line.

You can pan and zoom the live graph at any time: scroll to zoom, drag to pan. This is useful for inspecting recent samples while logging continues.

If the graph shows no data or the status bar shows connection errors, verify the IP address, port, and slave ID in Steps 1 and 2.

Step 5 — Navigate the graph

The Scale options panel at the bottom of the window controls how the axes scale.

  1. Under X axis, select Sliding window and set the interval to 60 seconds.

    The graph now shows only the last 60 seconds of data, scrolling forward as new samples arrive.

  2. Under Y axis, select Window auto-scale.

    The y-axis rescales automatically to the values visible in the current x-window.

You can also navigate with the mouse: scroll to zoom both axes, drag to pan. To zoom a single axis, click its label first, then scroll or drag. Double-click an axis label to reset it to auto-scale.

Step 6 — Stop logging

  1. Click Stop Logging when you have collected enough data.

The graph stops updating. You can continue to pan and zoom the captured data before exporting it.

Step 7 — Export to CSV

  1. Go to File > Save Data File As….

  2. Choose a folder and file name.

  3. Click Save.

Result: You have a .csv file containing timestamps and the values of all three registers, one column each.

What’s next