Comparison

FieldBus Toolkit vs LineKeeper

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

FieldBus Toolkit

Features
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FieldBus Toolkit is the essential utility for embedded engineers and PLC programmers. Debug Modbus TCP, MQTT, HTTP, and socket communications directly from your mobile device. [Key Features] 1. Multi-Protocol Support - Modbus TCP Client - MQTT Client (Publish/Subscribe) - HTTP REST Client (GET, POST, PUT, DELETE) - TCP/UDP Client & Server (Echo/Broadcast) 2. Data Visualization - Send and receive data in ASCII or HEX format. - Real-time communication logs. 3. Efficiency Tools - Save frequently used commands as Macros for quick access. - One-touch data transmission. 4. Developer Friendly - Perfect for testing Arduino, ESP32, Raspberry Pi, and industrial PLCs.

About

LineKeeper

Features
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LineKeeper turns your iPhone into a pocket HMI for the controllers on your plant floor โ€” Allen-Bradley Logix, Siemens S7, and anything that speaks Modbus TCP. Scan the network and the app finds every PLC around and tells you which ones are ready to talk. On Allen-Bradley it reads the controller's own tag list over EtherNet/IP โ€” live values in seconds, nothing to configure: no PLC program changes, no gateway, no OPC server, no cloud account. Values go straight from the controller to your phone. WHAT YOU CAN DO โ€ข Zero-config tag browser on Logix โ€” every tag of every PLC, live, with search, including program-scoped tags. โ€ข Find by action โ€” don't know the address? Press the machine's real button, or nudge a setpoint on its own screen, in the rhythm the app dictates โ€” and the app finds the tag that followed. Works on Modbus and S7 too, where there are no tag names at all. โ€ข Network scan โ€” one sweep fingerprints EtherNet/IP, Modbus TCP, S7 and more. A PLC with closed access shows as "found, access closed" with the exact steps to open it, down to the TIA Portal clicks. โ€ข One dashboard per machine, on multiple pages โ€” number, gauge, LED and trend tiles on swipeable named pages ("Filler", "Capper", "Conveyors"), even when one machine runs several PLCs. โ€ข Operator panel โ€” large start/stop buttons, hold-to-run jog, latches, setpoints and status lamps, full-screen kiosk mode with the screen kept awake. โ€ข Alarms and status codes โ€” alarm words mapped to operator texts, a red banner over every screen while an alarm is active, and a session journal of appeared/cleared. โ€ข Machine history โ€” a parameter snapshot of the controller taken at the first connection, plus a change log of every dashboard and panel tag: date and value of each change, kept on the phone across sessions. โ€ข Guarded writes โ€” every write is confirmed and validated against the tag type and limits; hold-to-run releases the moment the app loses focus. โ€ข Machine profiles โ€” PLCs, register maps, pages, panel and alarm texts saved as one profile and shared as a file: enter the register map once, the next shift sees names. โ€ข Built-in demo line โ€” two virtual PLCs with a working panel so you can learn the whole app with no hardware. LINEKEEPER PRO (IN-APP PURCHASE) Reading is free forever. A one-time Pro purchase unlocks, on real controllers: writing setpoints and driving the operator panel, plus machine history โ€” the parameter snapshot and the per-tag change log. Everyone who bought Write Unlock owns Pro automatically. The demo line includes every Pro feature free. WHO IT'S FOR Controls engineers, integrators and maintenance techs who need a quick window into a controller during commissioning, troubleshooting, or a line-down call โ€” without carrying a laptop. HOW IT CONNECTS Your phone must be on the same network as the controller (plant Wi-Fi that routes to the PLC, or a USB-C Ethernet adapter). There is no cloud relay: if you can ping the PLC, the app can connect. SUPPORTED CONTROLLERS โ€ข Allen-Bradley CompactLogix and ControlLogix (the tag-based Logix 5000 family) over EtherNet/IP; SLC-500 and MicroLogix over PCCC, with the major fault decoded in place; PLC-5 via the address book (experimental). โ€ข Siemens S7-300 and S7-400 out of the box; S7-1200 and S7-1500 with PUT/GET enabled and non-optimized DBs โ€” the app shows the exact TIA Portal steps. Absolute addressing: DB, M, I/Q. โ€ข Modbus TCP devices โ€” Schneider, VFDs, energy meters, WAGO, Delta and other Modbus slaves, with per-connection unit ID and word-order settings. Micro800, LOGO! and S7-200 use different protocols and are not supported yet. SAFETY Writing a value can move real machinery. You remain responsible for safe operation and must follow all site safety procedures. Never rely on the app for an emergency stop or any safety function. See the full terms at linekeeper.net/terms.html.

Screenshots

FieldBus Toolkit4 screens
LineKeeper4 screens

Verdict

The call

The clearest difference is ads: LineKeeper at none against FieldBus Toolkit's shown. LineKeeper also leads on update cadence (monthly vs every 3 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. FieldBus Toolkit sells 1 one-off in-app purchase and LineKeeper sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

FieldBus Toolkit ships an update every 3 months, LineKeeper monthly. The most recent releases landed on October 24, 2026 and October 21, 2026 respectively.

Scorecard2 real differences ยท 4 level
FieldBus Toolkit versus LineKeeper: the parameters behind the verdict, then further details
ParameterFieldBus ToolkitLineKeeper
PriceFreeFree
Update frequencyEvery 3 monthsMonthly โ€” better
AdsYesNo โ€” better
In-app purchasesYesYes
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.015.0
Further details โ€” not scored
Size28 MB22 MB
Age rating4+4+
DeveloperDONGSOO LEEOleksandr Makarov

In-app purchases

1 purchases

FieldBus Toolkit

One-time1
  • Remove Ads$1.99
1 purchases

LineKeeper

One-time1
  • Write Unlock$59.99

Questions

Is FieldBus Toolkit free?
FieldBus Toolkit is free to download, with in-app purchases available.
Is LineKeeper free?
LineKeeper is free to download, with in-app purchases available.
Do FieldBus Toolkit or LineKeeper have ads?
FieldBus Toolkit shows ads; LineKeeper does not.
Which is updated more often, FieldBus Toolkit or LineKeeper?
FieldBus Toolkit ships an update every 3 months, and LineKeeper monthly. Most recently, FieldBus Toolkit was updated on October 24, 2026 and LineKeeper on October 21, 2026.

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