Add signals

This guide shows how to add signals to monitor in ModbusScope.

Before you start

You must have at least one connection and one device configured. See Configure a TCP connection or Configure an RTU connection.

Steps

  1. Click Signals in the toolbar.

    Signals dialog

  2. Click Add to insert a new signal row.

  3. In the Expression column, enter the data point address using ${...} syntax (e.g. ${40001}). See Reference: Register syntax for all supported forms.

  4. In the Name column, enter a label for the graph legend.

  5. In the Color column, pick a line color.

  6. In the Y-Axis column, select Y1 or Y2.

  7. Use the Active checkbox to include or exclude a signal from polling.

  8. Repeat steps 2–7 for each signal.

  9. Click OK.

The data type is part of the expression (for example ${40001: s16b}); see the register syntax reference.

Result: The signals appear in the main window. They will be polled when you click Start logging.

Tips

  • To reference a specific device, add @DEVICE to the expression (e.g. ${40001@2} reads from device 2). Device 1 is used by default.

  • To calculate or combine values, use an expression instead of a bare address. See Write expressions.

  • Importing registers from a .mbc file is faster than adding them by hand. See Import from MBC file.

  • Consecutive data point addresses are read in a single Modbus packet. Gaps between addresses split the request and slow down the poll rate. See Optimize poll rate.

See also