About Modbus TCP FieldKit
FieldKit is a Modbus TCP toolkit for iPhone and iPad. Vladimir Chemeris, an independent developer, builds and supports it.
What it is for
You stand in front of a PLC, an energy meter or an RS-485 converter, and you want to know whether it answers and what it says. FieldKit gets you there from a phone: find the device, read the register, watch the value, confirm the write. The server mode gives you a device to test against when you have no PLC at hand.
The rules it keeps
- No subscription. You pay Apple once. There are no in-app purchases and no account.
- You confirm each write. The app stops on a sheet that lists the target and each value.
- Scans only read. Find devices and Scan Unit IDs send FC 03 reads and write nothing.
- The limits are on the page. The server runs in the foreground, iOS doesn't guarantee port 502, and the app has no direct RS-485 or USB connection. The site says so before you buy.
- You control diagnostics. Crash reports and anonymous usage counts start on, and you can turn each off in Settings. Read the policy.
Sources and tests behind the guides
The articles on this site come from the Modbus specification and from captures against a real server. Frames in the articles are real traffic: we ran pymodbus on a local machine, sent raw requests over a socket, and printed what came back. If a device or library broke the specification, the article says so. We name the version we tested.
These pages describe app version 1.2.1. The developer writes them from the app's code and its screens.
Other apps
iPerf3 Client & Server covers network throughput tests; MQTT Commander covers MQTT brokers. The developer's App Store page lists them.
Contact
Send bugs and feature requests to support@chama.pro. The support page answers the common setup questions.
