---
title: Modbus Tool
description: Ad-hoc Modbus TCP poller for verifying register maps during commissioning, independent of the production client/variable configuration.
source: https://documentation.controlcomtech.com/build/edge-server/web-interface/tools/modbus
---

# Modbus

`/tools/modbus` is an ad-hoc Modbus TCP poller that lets you read registers and coils without creating a real client in ControlCom Connect. Use it to check a register map against a live device during commissioning.

> **Workflow Stage: Collect**

**Clients table**

Add as many endpoints as you need. Each row has:

* **Host** and **Port** (default `502`).
* **Zero-based addressing** toggle, for devices that document addresses starting at 0 versus 1.
* A status indicator (idle, connected, error).

Press Enter in the Host field to spawn another client; click the remove icon to drop one.

**Polling rows**

Each row defines a single read:

| Field                               | Notes                                                              |
| ----------------------------------- | ------------------------------------------------------------------ |
| **Client**                          | Which configured client to read from.                              |
| **Unit**                            | Modbus unit ID (1–255).                                            |
| **Type**                            | Coils, Discrete Inputs, Holding Registers, or Input Registers.     |
| **Data**                            | Bit, Int16, UInt16, Int32, UInt32, Float, Int64, UInt64, Double64. |
| **Address**                         | 0–65535 (subject to Zero-based addressing).                        |
| **Bit**                             | 0–15 for bit-level access into a register.                         |
| **Scale**, **Offset**, **Decimals** | Display scaling.                                                   |
| **Live**                            | The most recent value (pulses when it changes).                    |

Add rows one at a time or bulk-insert N sequential addresses; expand any row to reveal **per-unit** decoding flags shared across every row on the same `(client, unit)` pair:

* **Big Endian**
* **Swap Words**
* **Force Write Many**
* **Request With Gaps**

**Controls**

* **Interval** (ms): polling cadence, clamped to a sane min/max.
* **Play / Stop**: start and halt the live stream.
* **Export Configuration**: download the current rows as CSV, useful for handing the verified map back to whoever maintains the cloud configuration.