---
title: Tags
slug: bhdo-v2/tags
createdAt: 2022-05-13T19:50:40.000Z
---

Tags are the single units of data collection from a device. Once you connect a device to Belden Horizon Data Operations, you add tags to that device. Tags map to the device's registers from which you want DeviceHub to collect data. Every device has memory registers that store sensor and system values. These registers can be analog and digital, input and output. Register information is accessed as tags and these tags are published as *Topics *to the internal *Message Broker*. 

# Raw Topics and Alias Topics

When you [Connect a Device](docId\:f8KfMKcZ3LqC-Pp0XisNe), you have the option of generating raw topics or alias topics. Alias topics consist of *devicename* and *tagname *instead of DeviceID and TagID. Topics can be used for publishing and subscribing with an internal message broker. Raw or processed data can be analyzed at the edge using [Analytics](docId\:r1e91qV2DghU3PzGtN1K_) or flows in [Flows Manager](docId\:GFfqhNUQlcx4axTjsyR8G). You can publish data to Belden Horizon Data Manager through raw topics.

You can add tags as follows:

- **Add a tag**: Adds a single tag for the selected device.
- **Upload a CSV file**: Uploads a list of tags from a CSV file.
- **Browse Tags**: Search for pre-defined device tags and select the ones to add. See [Search for Pre-defined Device Tags](docId\:jxjctIJtxGfVsZHHyYyVw) to learn more. 

See [Default Topics and Descriptions](docId:6Dt9FRzUswh0uYDWptLfB) for information about topic formats.

# Important

If you select *Enable alias topics* while adding or modifying a device:

- The Topic ID is replaced with a name (for example, `devicehub.alias.PLC1.floatTag`)
- DeviceHub stops publishing to raw topics and publishes only to alias topics. 
- Belden Horizon Data Operations substitutes all special characters in aliases with "\_" (underscore). 
- Message broker allows subscribe and publish of Raw/Alias topics. 
- When alias topics are enabled for a device, you can't use batch write topics. To use batch write topics, you must not select the **Enable alias topics** check box in the device configuration. See [Default Topics and Descriptions](docId:6Dt9FRzUswh0uYDWptLfB) for more information. 

# Access Tags UI

You can access *Tags *from the *DeviceHub*. 

**To access Tags:**

1. Log in to Belden Horizon Data Operations.
2. From the Navigation panel, navigate to **DeviceHub **> **Tags**.

   The* Tags* pane appears.

::Image[]{src="https://api.archbee.com/api/optimize/SSUUxKZUk9bFTEPNn_6Zo/8kAzKKjsdgNrVX5IX-vkK_tagsui.png" size="80" width="1434" height="570" caption="DeviceHub Tags pane" position="center" showCaption="true"}

# Next Steps

- [Add Tags](docId\:PYRa8tUvdoIeJm1luBm-O) 
- [Browse Tags](docId\:gplqFLn57jzR-oxOYNMaZ) 
- [Manage Tags](docId\:BJAXKSdBnWDDOszmP82t1) 
- [Tag Formula Variables](docId\:PHFk5OxDG8qWPlkFrAaC_)
- [Default Topics and Descriptions](docId:6Dt9FRzUswh0uYDWptLfB)
- [DeviceHub Guides](docId\:l8lWSXqLHl4IA0KKYPp3Q)
- [DeviceHub Troubleshooting](docId\:cus5bzWnMurFctQL76D83)