---
title: Testing an OPC-DA connection
slug: how-tos/v3uE-t
docTags: cUV_Sa6jBAIeXJcsVeSZ9
createdAt: 2025-09-09T08:21:05.115Z
---

## Step 1: Install an OPC-DA client

You need a tool to connect to and browse your OPC-DA server. Here are some free options:

| Client Name                     | Platforms | Link                                                                                          |
| ------------------------------- | --------- | --------------------------------------------------------------------------------------------- |
| Matrikon OPC Explorer           | Windows   | [Download](https://www.matrikonopc.com/downloads/176/software/index.aspx)                     |
| Integration Objects Test Client | Windows   | [Download](https://integrationobjects.com/sioth-opc/sioth-opc-free-tools/opc-da-test-client/) |

:::BlockQuote
Your OPC-DA server may offer a built-in explorer to browse the server without extra setup.
:::

## Step 2: Gather connection details

To connect, you'll need:

- Access to the OPC-DA server to install the OPC-DA client (an OPC-DA connection is **localhost traffic** only, except if dedicated OPC-DA tunnel software is installed)
- ProgID**:** most test clients can automatically detect this for servers on the local network

## Step 3: Browse Nodes

Once connected, you can browse the server to see the available OPC-DA items (with ItemID being the address), their current values, and more.

The example below shows how this works using Matrikon OPC Explorer, including how to export a list of ItemIDs to csv.

![](https://api.archbee.com/api/optimize/SMPo4IS9FkillUAMsur2c/sVPY61ubljUaoqm3SkUCU-20250918-142215.gif)

## Troubleshooting OPC-DA connection

### Windows OPC-DA clients only

OPC-DA is a legacy protocol that can only run on machines with DCOM technology, which is a proprietary Microsoft technology only running on Windows machines that are compatible with a 32-bit instruction set (64-bit Windows ≥ 10 machine is compatible).