--- title: Reading BACnet with Edge Server description: Configure a BACnet/IP or BACnet MS/TP client on the ControlCom Edge Server to read object properties into platform variables. source: https://documentation.controlcomtech.com/build/edge-server/clients/bacnet --- # Reading BACnet Data with ControlCom Edge Server A BACnet client connects the Edge Server to a BACnet controller over **BACnet/IP** (Ethernet) or **BACnet MS/TP** (RS-485 serial) and reads object properties into platform variables. You configure it from the platform in the device's SDK Configuration editor; the Edge Server picks the configuration up on its next restart. > **Workflow Stage: Collect** ## Prerequisites The Edge Server must already be onboarded as a ControlCom Gateway. The [Edge Server getting started guide](https://documentation.controlcomtech.com/build/edge-server/getting-started) covers deployment and onboarding. Each object you read needs a variable on the gateway to receive it. Create those first (see [Creating a Variable](https://documentation.controlcomtech.com/build/edge-server/creating-a-variable)); you select each variable by its Topic Property Path when you add an object below. The object editor also has a **Create New Variable** button if you prefer to create them as you go. ## Creating a BACnet Client 1. Open **Devices** under **System** in the sidebar and select the onboarded gateway. 2. Open the **Edge Server** tab. The **SDK Configuration** editor opens on its **Clients** tab. 3. Click **Add Client** and choose **BACnet IP** or **BACnet MSTP** in the **Add New Client** dialog. This guide uses BACnet IP. The new client opens in a side panel and also appears as a card on the Clients tab; click the card to reopen it later. New clients start disabled. BACnet MS/TP talks to the controller over a serial port, so the Edge Server container needs a volume mount for that serial device. This guide does not cover that setup. ![Edge Server Clients tab](https://documentation.controlcomtech.com/images/devices/edge-server-clients-screen.png) *Edge Server tab with no clients yet. Click Add Client to begin* ![Add New Client dialog](https://documentation.controlcomtech.com/images/devices/edge-server-add-client-screen.png) *Add New Client dialog with Modbus TCP, Modbus RTU, OPC UA, BACnet, and Ethernet/IP options* The client panel has three tabs: **Connection**, **Settings** and **Objects**. ### Connection Enter a **Client Name**, then fill in the transport-specific fields. For BACnet IP, enter the **Device Address** (the IP address of the controller, such as `192.168.1.100`) and the **Port** (defaults to `47808`, the BACnet/IP standard). **Routed network** and **Routed MAC (hex)** are only needed when the controller sits behind a BACnet router. For BACnet MSTP, enter the **Serial Port** path (such as `/dev/ttyUSB0`) and the **Baud Rate** (defaults to `9600`). **MAC Address** is the address the Edge Server claims on the MS/TP bus (`0` to `127`), and **Target MAC Address** is the controller's address on the bus; set it explicitly, because leaving it empty falls back to the Edge Server's own MAC Address, which only works when the two happen to match. **Max Master** (defaults to `127`), **Max Info Frames** (`1`), **Data Bits** (`8`), **Stop Bits** (`1`) and **Parity** (`none`, `even` or `odd`) can usually stay at their defaults. The remaining fields apply to both transports: 1. Enter the **Device Instance**, the BACnet device instance ID of the controller. 2. Set the **Poll Interval (ms)**, how often each object is read. Defaults to `1000`. 3. Set the **Timeout (seconds)**, how long to wait for a response before the request is treated as failed. Defaults to `15`. 4. Turn on **Enabled**. ### Settings The Settings tab holds maintenance actions: **Remove Client** deletes the client from this configuration, **Export Variables** downloads the object list as a CSV for bulk editing, and **Import Client Variables** loads an object list from a CSV. ### Objects An object is one BACnet property read from the controller. Click **Add Object**, then select the new entry in the list on the left. **Sort by Instance Number** keeps the list in order. On the **General** tab: 1. Select the **Object Type**: `AnalogInput`, `AnalogOutput`, `AnalogValue`, `BinaryInput`, `BinaryOutput`, `BinaryValue`, `MultiStateInput`, `MultiStateOutput` or `MultiStateValue`. 2. Enter the **Instance Number** of the object on the controller (`0` to `4194302`). 3. Enter the **Property Identifier**. It defaults to `85`, Present Value, which is what you want in nearly every case. Other common identifiers are `77` (Object Name), `28` (Description), `36` (Event State), `103` (Reliability) and `111` (Status Flags). 4. Optionally enter a **Write Priority** (`1` to `16`) used when the platform writes to this object. BACnet keeps a priority array where lower numbers win: `1` is Manual Life Safety, `2` Automatic Life Safety, `5` Critical Equipment, `8` Manual Operator and `16` the lowest priority. When left empty, writes use `16`. 5. Select the **Topic Property Path**, which is the variable that receives the value. The object's data type (number, boolean or string) follows the selected variable. 6. Optionally select a **Write Variable** to let the platform write to this object when a matching command is sent. The default is **No Write Allowed**. On the **Scaling** tab (number objects only), **Scale** (defaults to `1`) multiplies the raw value, **Offset** (defaults to `0`) is added after scaling, and **Decimals** (defaults to `2`) rounds the result. On the **Misc** tab, **Send if Stale After Milliseconds** forces a publish when the value has not changed in that time (defaults to `600000`, ten minutes), and **Deadband Percentage** (defaults to `5`, number objects only) suppresses changes smaller than that share of the previous value. On the **Transforms** tab you can add [Value Transforms](https://documentation.controlcomtech.com/build/edge-server/data-processors#value-transforms) that rewrite the value before it is published. ## Saving Click **Save Configuration** in the editor header, then confirm with **Save Configuration** in the **Save SDK configuration?** dialog. The configuration is stored on the platform; the gateway applies it on its next restart. ## Deployment The Edge Server reads its configuration when it starts, so a restart is what puts the new client into service. There are two ways to trigger one. From the platform, open the gateway's **Details** tab and click **Restart** in the **Send command** panel. The Edge Server restarts and reconnects with the new configuration. [Edge Server Management](https://documentation.controlcomtech.com/platform/devices/edge-server#sdk-commands) describes the full set of SDK commands. On the gateway itself, restart the container as described in the [Edge Server getting started guide](https://documentation.controlcomtech.com/build/edge-server/getting-started). ![Restarting Device](https://documentation.controlcomtech.com/images/devices/device-details-page.png) *The Details tab, with the Send command panel used to restart the Edge Server*