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# BACnet wiring

The receiver **RX BACNET** offers dual connectivity to adapt to all industrial supervision architectures (PLCs, IoT Gateways, industrial PCs).

## Communication modes

Depending on your infrastructure, you can use one of the following two interfaces:

* **BACnet IP** : Connection via the integrated RJ45 port. This mode uses the Ethernet network to carry Modbus frames.
* **BACnet MSTP** (Serial): Use of the RS485 link via the pre-wired multicore cable.

## Pinout and Color Code (Serial Link)

The RX BACNET comes with a pre-wired cable for serial links. Please strictly follow the color code below when connecting it to your PLC:

**RS485 Link (Preferred for long distances)**

<table><thead><tr><th width="150.4609375">Wire color</th><th width="134.734375">Signal</th><th>PLC connection</th></tr></thead><tbody><tr><td><mark style="color:orange;">Brown</mark></td><td>A (+)</td><td>RX terminal / A of the PLC</td></tr><tr><td>White</td><td>B (-)</td><td>TX terminal / B of the PLC</td></tr><tr><td><mark style="color:$success;">Green</mark></td><td>GND</td><td>PLC ground (GND)</td></tr></tbody></table>

## :warning: Recommendations

To ensure efficient communication between your PLC and the RX BACNET, we recommend following these recommendations:

{% hint style="danger" %}
**Delay** : If you do not use Change of Value (COV), we recommend keeping a delay of at least two seconds between two consecutive BACnet request sends to the receiver. As a reminder, the minimum periodicity with which Enless transmitters can be configured is one minute. It is therefore not necessary to configure very high polling frequencies.
{% endhint %}

{% hint style="danger" %}
**Limit** : The number of COV (Change of Value) subscriptions must not exceed 80
{% endhint %}


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