Modbus TCP tester for Windows

Connect to a Modbus TCP device

Open Connection Setup, choose Modbus TCP/IP, enter the IP address or host name and the server port (502 by default) and press Connect. You can set the response timeout from 50 ms to 60 seconds and a delay between polls. Every poll window shares this one connection, so you open the link once and then add as many windows as you need.

Poll coils, discrete inputs and registers

A poll window reads one block of data with function 01 (coils), 02 (discrete inputs), 03 (holding registers) or 04 (input registers). You choose the slave ID, the start address, the quantity (up to 2000 for coils and discrete inputs, up to 125 for registers) and the scan interval in milliseconds. A typical setup uses one window per block of a device: one for the process values, one for the status words, one for the settings.

Read values the way the device means them

Registers are only 16 bits, but devices pack floats, long integers and text into them. Busscope offers 12 display formats (Signed, Unsigned, Hex, Binary, ASCII, Long, Long Unsigned, Long Hex, Float, Double, Int64 and UInt64) in four byte and word orders, so a 32-bit float from a device with a different word order still shows the right number. Set the format per cell, for a selection or for the whole window. You can also name cells and add value labels such as 1=Running; the names appear in charts, log headers and print-outs.

Write with a confirmation

The write dialog (Ctrl+Shift+W) covers the write functions 05, 06, 15, 16, 22 and 23. Double-clicking a value in a poll window writes a single coil or register after you confirm the address and the value. Writing to industrial equipment can have physical consequences, so Busscope never writes silently, and you stay responsible for every write, as the EULA says.

See what happens on the wire

The traffic panel (F4) lists every transmitted and received frame as hex with a time stamp, which is often the quickest way to see why a device does not answer. The diagnostics window (F7) sends exception status (07), diagnostics (08, all sub-functions), comm event counter (11), report slave ID (17) and read device identification (43/14).

Script requests and probe unknown devices

The Request Runner executes a list of requests and checks each result against an expectation: OK, an exception code (EX 2), TIMEOUT or an exact response in hex. Lists are saved and loaded as JSON, which makes regression checks of a device repeatable. The Register Probe scans an address range and reports which addresses are readable and which return an illegal-address exception.

Log, print and save your setup

Log polled values to CSV or Excel (.xlsx), open a print preview of any window and save the whole setup (connection, windows, formats, names, charts and auto-connect) as a workspace file.