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Modbus · RTU / ASCII / TCP

Modbus, decoded and built

See every Modbus frame paired and labelled, annotate registers with real names and units, and build valid commands without touching a CRC table.

Download free for 30 days vs Modbus Poll

Decode RTU, ASCII & TCP

All three transports, with request↔response pairing and exception decoding.

Build any function code

FC 01–06, 0F and 10 — CRC (RTU) and LRC (ASCII) appended automatically.

Register maps & values

Annotate registers with names, data types (U16/S16/U32/F32…), scaling and units.

Online device library

Pull verified maps so a meter or drive decodes by name the instant you connect.

Value parsing

Every frame, decoded and paired

Raw Modbus is hard to read at speed. Omni Console pairs each request with its response and turns the payload into labelled registers and values — so a bad CRC, an exception or an off-by-one address jumps out immediately.

  • Slave/unit ID, function, data and CRC/LRC — or the MBAP header for TCP
  • Requests paired with responses; exceptions named (e.g. ILLEGAL DATA ADDRESS)
  • Registers annotated with names, types, scale and units from a map
About the device library
Omni Console — Modbus RTU
Protocol Modbus RTU
MIXED HEX ASCII
COM9 · 9600 8N1 RX 1.2 kB TX 96 B Auto-scroll
10:17:56.178  — opened COM9 @ 9600 8N1
10:17:58.041  TX  11 03 00 6B 00 03 76 87
→ Read Holding · slave 0x11 · regs 107–109
10:17:58.094  RX  11 03 06 00 E6 00 32 03 F5 5A 9D
→ 3 registers = 230, 50, 1013 (V · Hz · mbar)
10:18:02.610  TX  11 06 00 10 00 01 8C 9B
→ Write Single Register · addr 16 = 1
10:18:02.658  RX  11 86 02 C3 A1
→ exception 02 · ILLEGAL DATA ADDRESS
10:18:05.331  RX  11 03 06 00 E4 00 32 03 F2 ▋
Quick send 11 03 00 6B 00 03 HEX Send
Command creating

Create and send valid frames

Build a request from a simple form — pick the function, address and quantity — and Omni Console assembles the bytes and appends the checksum. No more hand-counting CRCs.

  • Function codes 01–06, 0F and 10
  • RTU and ASCII framing with CRC / LRC computed automatically
  • Save as a named sequence and fire it from quick-send
Omni Console — Build Modbus frame
Build Modbus frame
Transport RTU
Slave 0x11
Function 03 · Read Holding Registers
Address 107
Quantity 3
Frame preview
11 03 00 6B 00 03 76 87
CRC-16 appended automatically Send

Speaks raw, too — not just the named protocols

Point Omni Console at any serial device and read the line in ten display modes — ASCII, HEX, Mixed, Decimal, Binary, Raw and Events — with full-text search and export. It also decodes the proprietary O1TP framing out of the box. Modbus, DLMS, M-Bus, IEC 62056-21 and MASS simply get the extra layer: deep value parsing that turns bytes into labelled, unit-aware readings — plus command builders for Modbus, M-Bus and DLMS.

See every feature
Modbus questions

Modbus, answered

Does it support Modbus RTU, ASCII and TCP?
Yes — all three. Frames are decoded with slave/unit ID, function code, data and CRC/LRC (or the MBAP header for TCP), and requests are paired with their responses.
Can it build and send Modbus commands?
Yes. The frame builder creates valid messages for function codes 01–06, 0F and 10, computing the CRC or LRC for you. Save them as sequences and fire them from quick-send.
Is this a good Modbus Poll alternative?
For monitoring, decoding and building frames across RTU/ASCII/TCP — plus an online device library — many users find it a modern fit. See the full comparison.
How do register maps work?
Load a device's register map (from the online library or your own TOML) and Omni Console annotates response registers with names, types, scaling and units.

Explore the other protocols

DLMS / COSEM HDLC, OBIS, AES-GCM, HLS M-Bus Self-describing DIF/VIF IEC 62056-21 Mode A–E sign-on MASS Turkish metering standard

Put Modbus on the bench.

Download Omni Console and decode your first Modbus frame in minutes — free for 30 days.

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