---
title: "Virtual Tags"
slug: "virtual-tags"
updated: 2026-10-27T23:11:33Z
published: 2026-10-27T23:11:33Z
canonical: "ims-handbook.cenosco.com/virtual-tags"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://ims-handbook.cenosco.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Defining Virtual IOW Tags

A Virtual Tag is a way of defining IOW Tags using dynamic expressions. Expression can be composed using PI Tags and built-in functions like:

- +, -, *, /
- MIN, MAX, MEAN, SUM, ABS, SQRT, STD
- If then else
- ( )

## Creating Virtual Tags

To create a Virtual Tag:

- First [create a new IOW](/v414/docs/creating-iows).
- For the Variable select "Virtual Tag".![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(422).png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)Select the "Virtual Tag" Variable for your IOW.
- Now the Expression field becomes available. You can either click the *Edit* button and [define the Expression](/v414/docs/virtual-tags#defining-the-expression) right away, or do this later after you have saved your IOW.
- Remember to also fill in the other fields - refer to the [IOW Record](/v414/docs/iow-main-screen#iow-record).

## Opening the Expression

### From the CL/System Details Page

To open the Expression from the [CL Details Page](/v414/docs/creating-a-corrosion-loop) (PEI Equipment) or System Details Page (PLSS Equipment):

- Scroll to the IOW section.
- Find your Virtual Tag (Variable = "Virtual Tag").
- Click on the PI/Virtual Tag field.

![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(423).png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)Click in the PI/Virtual Tag field. 

- Then click the *Edit* button the becomes available.

![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(424).png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)Click the *Edit* button.

- Now you can define the Expression.

### From the IOW Details Page

To open the Expression from the [IOW Details Page](/v414/docs/iow-details-page):

- In the Details section, click **Edit**.
- In the Expression field click on the *Edit* button.

![](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pic%201(425).png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)The Virtual Tag Expression can also be opened from the IOW Details Page.

## Defining the Expression

Below is an example where a Virtual Tag expression is defined and verified. You can select a PI Tag from the list and click the **Add** button to add the Tag to the expression. When done defining the expression, you can verify it by clicking the **Test** button.

![Table  Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pei-release-pei-2022.1-image-fao62haa.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)A PI Tag is added to the expression with the Add button. The Test button is used to verify the expression.

When the Virtual Tag’s expression is verified, IMS will either show a green valid message or a red error message.

![Table  Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pei-release-pei-2022.1-image-6nzyqmjo.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)An error message is shown in case of, e.g., a syntax error in the expression. 

You can learn more about the Formula Editor [here](/docs/formula-editor).

### Tags search using wildcards

When adding Tags to the IOW (also when adding it to a Virtual Tag expression), you can search for the Tag name using wildcards in the search string. Valid examples are:

- *Test* (this is also default behavior when no wildcard is used)
- Test*
- *Test
- Test

![Graphical user interface, application  Description automatically generated](https://cdn.document360.io/e492a0e0-a4ba-4aca-8fc6-76b95f91fdf3/Images/Documentation/pei-release-pei-2022.1-image-r2s2vdew.png?sv=2026-02-06&spr=https&st=2026-10-28T13%3A36%3A11Z&se=2026-10-28T14%3A36%3A11Z&sr=c&sp=r&sig=RZTyxP6eIybrQct3qV73iyUJPfw3m8gi3qlRw7KFW4M%3D)Searching for a PI Tag using wildcards. 

###