> 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/fu-tx320-english-v1/communication/modbus-rtu-protocol/read-write-memory-ram/read-write-memory-read-listx.md).
# Read/Write Memory – Read Listx
{% hint style="info" %}
When reading large values with different data formats (e.g., **Float32** or **Int64**), tiny differences may occur due to internal calculations, typically **less than 1/10,000**, which is normal.
**Read commands** must not exceed **20 registers**; longer requests will be **ignored**. See the register list for details.
{% endhint %}
### How to Use the Read/Write Memory List
| Field Name | Function |
| ------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| Register Address | Addresses for read/write memory, not shared with read-only memory. |
| Register Length | Length of the register variable. |
| Memory Content Name | Describes the name or purpose of the memory content. |
| Data Type | Specifies the format of transmitted or received data. |
| Read Command | Indicates the available read commands. |
| Write Command | Indicates the available write commands. A value of X in this column means remote writing is not supported for that register. |
## Read-Write Memory List
### **Example: C02 Del Total (clear/reset totalized flow)**
| Step | Value |
| ------------------------------------------ | ------------------------ |
| Table Register Address (Hex) | 0x0201 |
| Converted to decimal | 0x0201 = 2×256 + 1 = 513 |
| Master address to enter (4xxxx convention) | 40001 + 513 = 40514 |
| Address bytes in the frame | 02 01 |
| Full write frame (station 01) | 01 06 02 01 00 01 18 72 |
If `40201` is entered by mistake, the master sends decimal `200` (`0x00C8`) — an address that doesn't exist. The flow meter won't respond, or may return exception code 02; on the PLC side this appears as "no response to write."
### Self-verification tip
If you're not sure which address convention your master uses, first use function code 03 to read the register that corresponds to Modbus ID. If the value read back matches the device's own station number, the address base is correct and you can safely apply the same convention to the other addresses.
---
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