> 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-english-v5/installation-and-setup/electronic-installation.md).

# Electrical installation

{% hint style="danger" %}
**Safety First:** Do not perform wiring while the unit is powered on. Before any wiring work, turn off the power and disconnect the power supply.
{% endhint %}

{% hint style="danger" %}
**CRITICAL WARNING**: **Do not apply overvoltage to communication lines**\
The Modbus RS-485 communication lines (A/B) have a maximum rated voltage of typically 5 V. They must never be connected to or share continuity with the flowmeter's DC 24 V power lines. Incorrect wiring will instantly destroy the internal core components of the flowmeter. Damage caused by wiring errors is not covered under warranty. Always verify all wiring with a multimeter before powering on the device.
{% endhint %}

## **6-Pin Quick Connector Pin Definition**

* Connect the supplied cable to the power supply and the required communication interfaces. Unused wires must be insulated with protective material to prevent electric leakage or short circuits.
* Before opening the unit or performing any wiring, turn off the power and disconnect the power supply.
* Due to space limitations, the label on the side of the unit and the following diagrams show **wire pin definitions only**.

The 6-pin quick connector wire color assignments are defined as follows:

![Cable Pin Map](/files/e8381e825df9ddabde59aabc836bc60e4d7026b1)

<table data-full-width="false"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td>1</td><td>Brown</td><td>24 VDC (+)</td></tr><tr><td>2</td><td>Black</td><td>RS485 (B-)</td></tr><tr><td>3</td><td>Green</td><td>RS485 (A+)</td></tr><tr><td>4</td><td>Orange</td><td>NPN output (+)</td></tr><tr><td>5</td><td>Purple</td><td>4~20mA (+)</td></tr><tr><td>6</td><td>Blue</td><td>0 VDC (-)</td></tr></tbody></table>

### 24V DC Power Wiring Diagram

* **Brown wire**: 24 VDC (+)
* **Blue wire**: 0 VDC (–)

<div align="left"><figure><img src="/files/VMOhTe3l7rjDRrbDFrjl" alt="" width="563"><figcaption></figcaption></figure></div>

### 4–20 mA Analog Output Wiring Diagram

* **Brown wire**: 24 VDC (+)
* **Blue wire**: 0 VDC (–)
* **Purple wire**: 4–20 mA (+)

<div align="left"><figure><img src="/files/8kF3ZHnBdHzTwuM6Wtaj" alt="" width="563"><figcaption></figcaption></figure></div>

### **NPN Output Wiring Diagram**

* **Brown wire**: 24 VDC (+)
* **Blue wire**: 0 VDC (–)
* **Orange wire**: NPN Output (+)

<div align="left"><figure><img src="/files/2uj82ey3Hxy2NKQAD6hf" alt="" width="563"><figcaption></figcaption></figure></div>

### **RS-485 Two-Wire Wiring Diagram**

* **Black wire**: RS-485 B (–)
* **Green wire**: RS-485 A (+)

<div align="left"><figure><img src="/files/y9CJSIhZW30E4W75C1FG" alt="" width="563"><figcaption></figcaption></figure></div>

{% hint style="info" %}

#### RS-485 Wiring Recommendations

* It is recommended to use **shielded 24 AWG twisted-pair cable** and connect devices in a **daisy-chain configuration**. Do not use star or ring wiring.
* For long cable runs, install **termination resistors** at both the master and the farthest device. A typical value is **120 Ω**, but the actual value should be calculated based on the cable specifications.
* If signal instability occurs, consider adding **bias resistors** at a point along the line.
* For the supplied 6-core cable, when used for RS-485 communication, **trim excess length** to minimize noise interference. Route the shield braid along with the main communication wires and **ground it**.
* In areas with heavy signal interference, the software may need to **poll multiple times** to receive a response. Implement a **repeated polling mechanism** in the communication program to distinguish between signal interference and actual device offline conditions.
  {% endhint %}


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