# About HMI tag names

HMI tag names can be up to 255 characters long and can contain the following characters:

- A to Z
- 0 to 9
- underscore (_) and dash (-)

Use the backslash (\) to separate the parts of a tag name in a folder. For example, the tag name tanks\oil\temperature would be a tag named temperature in the oil folder, which is in the tanks folder.

You can use mixed case. Tag names preserve upper and lower case for readability but are not case sensitive. For example, the tag name MixerValve1 is the same as mixervalve1.

Tip: | When a tag name contains a dash (-), to use it in an expression, enclose the name in braces { }; for example, {N33-0}. Use braces when using wildcards to represent multiple tags in an expression, for example, {alarm*}.

## See also

Use wildcard characters

Create HMI tags