A Modbus TCP tool for field technicians and integrators
When you only need to know whether a device answers and what it says, a laptop is a lot to carry up a ladder. FieldKit does those checks from your phone.
A commissioning visit
- Find what’s on the network. Find devices lists hosts that answer on
502,1502,8899and4196. - Confirm the addressing. Read a small range in
0-based,1-basedorPLC 4xxxxnotation and compare with the manual. The off-by-one test. - Watch the value. Add it to Live monitoring and move the sensor or change the setpoint. Check that the chart follows.
- Write with a check. The confirmation sheet shows host, port, Unit ID, framing, function code and each value.
- Leave evidence. Export a CSV of the readings or a sanitized JSON log for the commissioning file.
Save the work for the next site
A profile stores endpoints and register definitions: format, byte and word order, scale, unit. Set up a device model once, and the next one of that model only needs a new IP address. Export sanitized profiles to a colleague: the default export removes hosts, labels and values.
Troubleshooting from the phone
A timeout gets a hint to check the Unit ID, plus a one-read test with the other framing. Exceptions appear by name. The timeout checklist walks through the layers.
Limits to know
Modbus TCP and RTU over TCP only, so a direct serial port still needs your laptop. Monitoring runs while the app is open, and it keeps the last 600 points or 1 hour per value, so it’s no replacement for a historian.