# 12. HMI internal registers

HMI provide four types of HMI address for user.

\*HSW, HDW, HPW, RPW are word address, HSX, HDX, HPX are bit address;

**1) System Parameters (HSW/HSX)**

The address starting with "HSW" are reserved by HMI system, define those address to save the state or parameter of current system. Like system properties, communication parameters etc.

**2) User Data (HDW/HDX)**

The address starting with "HDW" are provided for user, saving data to this type of address;

**3) Special Data (HUW/HUX)**

Special address reserved by HMI.

**4) System Data (HAW/HAX)**

Addresses in this area are latched, using for storing system data.

✎**Note:**

 HSW / HSX are a system special register, so please check the system special register list during use. Please use the address specified in the table and do not use the address which is not mentioned in the table;

 HUW/HUX is a system special register, so please check the system special register list during use. Please use the address specified in the table and do not use the address which is not mentioned in the table.

 HSW/ HDW/ HUW/ HAW is related to HSX/ HDX/ HUX/ HAX, (e.g. one-word address HSW0 contains 16 bits from HSX0.0 to HSX0.15);

###


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://wecon.gitbook.io/pistudio-manual/12.-hmi-internal-registers.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.