CS141 BACNET settings

With firmware release 1.88, the official BACnet standard is supported. You will find this menu only after running an update to at least this firmware version.

The Past of BACnet

In 1987, ASHRAE formed the SPC2 135P committee, including members from companies like Andover Controls, Honeywell, and Trane, to establish a communication protocol for building energy management. After several proposals, BACnet was adopted as the ASHRAE/ANSI standard in December 1995 and later recognized in Europe as DIN V ENV 1805-1. BACnet has since become a widely used standard in the U.S., enabling flexible and expandable building automation.

The future of BACnet: BACnet over IP

With BACnet over IP, BACnet goes on:

Existing IT infrastructures can be used, which significantly reduces costs for implementation. Ultimately, you only need a few BACnet-compatible network infrastructure devices like routers and switches with today's standard RJ45 ports.

Requirements

BACnet over IP is based on existing TCP / IP structures but extends these by a lot of functions that are required in building automation. It is important that a BACnet device only works if the corresponding infrastructure supports routing the BACnet extended protocol - for example, routers and switches must also be able to handle BACnet over IP. Alternatively, BACnet-compatible routers must be installed to connect BACnet segments with each via common network hardware. For the exact configuration of the existing BACnet infrastructure, please contact your local system administrator.

Required ports to use BACnet over IP

BACnet uses the UDP protocol and usually these standard ports:

• 47808 or 47809

Note:

Unlike e.g. Modbus, the standard ports do not follow standards in port binding. Due to this fact, BACnet does not specify any port that must be used for devices:

You can set up any port for your BACnet system your IT infrastructure uses. However, more modern BACnet port objects require support in the areas 47808 - 47823 (0xBAC0 - 0xBACF) and for the dynamic port areas 49152 - 65535 

Please refer to your local system administrator for the correct port settings.

For this configuration step, you need the following menus:

BACnet over IP does not work “out of the box” - some configuration work is required. To do this, open the menu services and click on BACnet. The following configuration menu will be presented:

Device ID

The Device ID is a unique, unsigned decimal number assigned to each BACnet device within a network. Its value is usually between 0 and 4,194,302. Every device in a BACnet network must have a unique Device ID, regardless of which physical network segment it is in. Even devices that communicate via MS/TP and therefore have a MAC address need a unique device ID in order to be clearly identifiable in the BACnet network.

MS/TP devices often communicate with BACnet/IP devices via a gateway, with the Device ID serving as the primary identification.

Network ID

The Network ID is a unique identifier within an IP network that indicates which network segment a device belongs to. It is comparable to the zip code of an address, which determines the location. Each device on an IP network requires a unique IP address, which consists of the Network ID and the Host ID. The Network ID defines the network area, while the Host ID identifies the device within this area.

It is important that Network IDs are unique within a network to ensure correct communication between devices. If a device is moved to a different network segment, the Network ID usually also needs to be adjusted. Network IDs are assigned either statically by a network administrator or dynamically via the Dynamic Host Configuration Protocol (DHCP).

APDU Timeout

APDU are the "Application Layer Protocol Data Units", the current data packet that is running through your BACnet network. The timeout is the time in milliseconds that the CS141 waits before assuming the loss of a data packet. Why the data packed is lost, can be very different and depends on the network setup.

Device Description

Enter a small description of the function of this device. When querying the CS141 with a BACnet browser, this information is displayed as "device description".

Device Location

Enter the physical location of the device. In case of problems, you will know where this device is installed.

Model Name

This is a free text description of the connected devices, e.g. the UPS or the registration number of a BACS system, etc. This field can be used to provide additional information for technical staff via BACnet.

UDP Port

As a default setting, the CS141 uses port 47808.However, since BACnet does not have any port restrictions by caused by standards, you may assign a port of your choice to fit the CS141 to your existing IT infrastructure

Enable / Disable BACnet

After configuration work is done, enable/disable BACnet support at Services> Configuration by setting the slider for BACnet to ON. The CS141 will enable the corresponding service and start providing BACnet data as configured.