Register Pocket

Register Pocket reads the registers of a Modbus TCP device from an iPhone or iPad, records what they do over time, and writes to them under a lock, a confirmation and a verified read-back. It is built for the moment at the machine when the laptop is in the car: connect, watch the numbers, prove what changed, and leave with a report. WRITING, THE CAREFUL WAY • Every session starts read-only. Unlocking is deliberate, and dropping the link re-locks it • A write is shown as "this address, this value, from this to this" before it goes • Written, then read back and compared — a write is "verified" only when the device agrees • Every write is logged with its before and after, and the log exports with the session A SESSION YOU CAN HAND OVER • Record while you watch: every poll, every tag, with timestamps • Export to CSV, or to xlsx that opens in Excel and Numbers with a sheet per device • The traffic window keeps the raw frames — timestamp, TX/RX bytes, round-trip time, and the device's own exception text — so "it does not answer" becomes evidence NUMBERS THE WAY THE DEVICE MEANS THEM • Int16, UInt16, Int32, UInt32, Float32, Int64, UInt64, Float64 • All four word and byte orders — ABCD, CDAB, BADC, DCBA — chosen per tag, not guessed • Show a register as a number, as hex, as bits, or as ASCII; scale and offset for engineering units • Coils, discrete inputs, input registers and holding registers, 0- or 1-based addressing WATCH MORE THAN ONE MACHINE • Several devices polled at once, each with its own connection, log and write lock • A live chart per tag, with gaps drawn dashed where nothing came back • MODBUS/TCP and RTU over TCP, for a serial gateway in transparent mode NO PLC? THE APP HAS ONE • A built-in demo device with a full register map — coils, discrete inputs, input and holding registers — that writes, refuses out-of-range addresses, and moves while you watch • Free, and the same device this app's own tests run against FREE, AND ONE UNLOCK Free: connecting, reading every table, the live chart, the traffic window, every data type and byte order, and the demo device. One-time unlock: writing, session recording with CSV/xlsx export, and device presets. Not a subscription. Polling runs while the app is on screen — there is no background polling, no relay server, and no data collection. English, Korean and Simplified Chinese. MODBUS is a registered trademark of Schneider Electric USA, Inc., licensed to the Modbus Organization. Register Pocket is an independent app and is not affiliated with or endorsed by either. From TECHSENSE — makers of TestBench Viewer, SQLite Viewer by TECHSENSE and DBF Viewer. More at testbench.tools