> For the complete documentation index, see [llms.txt](https://docs.lorric.com/qr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lorric.com/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/single-bit-data-read-write-commands-01-05-commonly-used-in-hmis.md).

# Single Bit Data Read/Write Commands (01/05) (Commonly Used in HMIs)

[<sub><mark style="background-color:blue;">**Purpose and Use Cases:**<mark style="background-color:blue;"></sub> <sub><mark style="background-color:blue;"> </sub><sub><mark style="background-color:blue;">Certain Human-Machine Interfaces (HMIs) only support the<mark style="background-color:blue;"></sub> <sub><mark style="background-color:blue;"> </sub><sub><mark style="background-color:blue;">**05 Write Command**<mark style="background-color:blue;"></sub> <sub><mark style="background-color:blue;"> </sub><sub><mark style="background-color:blue;">to send a signal to<mark style="background-color:blue;"></sub> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">reset the accumulated total. Additionally, some HMIs require support for the</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">**01 Read Command**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">to verify that the sensor is functioning correctly.</mark>](#user-content-fn-1)[^1]

## **01 Command Example**

This command does **not reset** the **C02.Del.Total** (Clear Accumulated Total) option. It only provides the HMI with the ability to read Single Bit data using the 01/05 commands. If the command format is correct, the flow meter will respond to the master device with a Bit read acknowledgment.

#### **Control Terminal TX (Transmit) Command Example for 01**

| Byte#          | 1             | 2             | 3                                | 4                                | 5                   | 6                   | 7   | 8   |
| -------------- | ------------- | ------------- | -------------------------------- | -------------------------------- | ------------------- | ------------------- | --- | --- |
| Node ID        | Slave Address | Function Code | Starting Address of Data to Read | Starting Address of Data to Read | Data to Read (Bits) | Data to Read (Bits) | CRC | CRC |
| Example 01\~FF | 01            | 01            | 02                               | 01                               | 00                  | 01                  | AD  | B2  |

#### **Control Terminal TX (Transmit) Command Example for 01**

* **Slave Address:** `01` (Address of the flow meter)
* **Function Code:** `01` (1-bit Read Command)
* **Starting Address of Data to Read:** `02 01` (Start address for C02.Del.Total Clear Accumulated Total)
* **Data to Read (Bits):** `00 01` (Read C02.Del.Total data)
* **CRC:** `AD B2` (Error-checking code calculated using the CRC algorithm)

#### **Flow Meter RX (Receive) Response Example for 01**CommentShare feedback on the editor

| Byte#          | 1             | 2             | 3            | 4            | 5   | 6   |
| -------------- | ------------- | ------------- | ------------ | ------------ | --- | --- |
| Node ID        | Slave Address | Function Code | Response Bit | Response Bit | CRC | CRC |
| Example 01\~FF | 01            | 01            | 01           | 00           | 51  | 88  |

* \
  **Slave Address:** `01` (Address of the flow meter)
* CommentShare feedback on the editor**Function Code:** `01` (Read Command)
* CommentShare feedback on the editor**Response Bit:** `01 00` (The flow meter is still online and operational, responding to the control terminal)
* CommentShare feedback on the editor**CRC:** `51 88` (Error-checking code calculated using the CRC algorithm)

## **05 Command Example**

<mark style="background-color:blue;">This example activates the</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">**C02.Del.Total**</mark> <mark style="background-color:blue;"></mark><mark style="background-color:blue;">option to clear accumulated data, resetting the total to zero.</mark>

#### **Control Terminal TX (Transmit) Command Example for 05**

| Byte#          | 1             | 2             | 3                                 | 4                                 | 5             | 6             | 7   | 8   |
| -------------- | ------------- | ------------- | --------------------------------- | --------------------------------- | ------------- | ------------- | --- | --- |
| Node ID        | Slave Address | Function Code | Starting Address of Data to Write | Starting Address of Data to Write | Data to Write | Data to Write | CRC | CRC |
| Example 01\~FF | 01            | 05            | 02                                | 01                                | FF            | 00            | DC  | 42  |

* **Slave Address:** `01` (Address of the flow meter)
* **Function Code:** `05` (Register Write Command)
* **Starting Address of Data to Write:** `02 01` (Start address for C02.Del.Total Clear Accumulated Total)
* **Data to Write:** `FF 00` (Reset C02.Del.Total data)
* **CRC:** `DC 42` (Error-checking code calculated using the CRC algorithm)

#### **Flow Meter RX (Receive) Response Example for 05**tor

| Byte#          | 1             | 2             | 3                                 | 4                                 | 5             | 6             | 7   | 8   |
| -------------- | ------------- | ------------- | --------------------------------- | --------------------------------- | ------------- | ------------- | --- | --- |
| Node ID        | Slave Address | Function Code | Starting Address of Data to Write | Starting Address of Data to Write | Data to Write | Data to Write | CRC | CRC |
| Example 01\~FF | 01            | 05            | 02                                | 01                                | FF            | 00            | DC  | 42  |

* **Slave Address:** `01` (Address of the flow meter)
* **Function Code:** `05` (Register Write Command)
* **Starting Address of Data to Write:** `02 01` (Memory address for C02.Del.Total Clear Accumulated Total)
* **Data Written:** `FF 00` (Acknowledgment of reset action sent back to the control terminal)
* **CRC:** `DC 42` (Error-checking code calculated using the CRC algorithm)

[^1]:


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

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

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.lorric.com/qr/fp-as310-paddle-wheel-flowmeter-manual-en-v1/communication/modbus-rtu-protocol/single-bit-data-read-write-commands-01-05-commonly-used-in-hmis.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

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.