BACnet™ Communication Interface for Chiller (BCI-C)

Overview

The BACnet™ Communication Interface for Chillers (BCI-C) is comprised of a Tracer™ UC400 controller with interface software. It is a non-programmable communications module that allows heating, ventilation, and air-conditioning (HVAC) equipment to communicate on a BACnet communications network.

This guide provides:

• A brief overview of the BACnet protocol
• An explanation of the BCI-C device rotary switches and LEDs
• Data point configuration property definitions
• Tables listing object data points
• Additional resources
• A glossary of terms

Note: Users of this guide should have basic knowledge of BACnet protocol. For more detailed information about this protocol, visit the company web site listed under "Additional Resources," p. 25.

BACnet Protocol

The Building Automation and Control Network (BACnet and ANSI/ASHRAE Standard 135-2004) protocol is a standard that allows building automation systems or components from different manufacturers to share information and control functions. BACnet provides building owners the capability to connect various types of building control systems or subsystems together for a variety of reasons. In addition, multiple vendors can use this protocol to share information for monitoring and supervisory control between systems and devices in a multi-vendor interconnected system.

The BACnet protocol identifies standard objects (data points) called BACnet objects. Each object has a defined list of properties that provide information about that object. BACnet also defines a number of standard application services that are used to access data and manipulate these objects and provides a client/server communication between devices. For more information on BACnet protocol, refer to "Additional Resources," p. 25.

BACnet Testing Laboratory (BTL) Certification

The BCI-C supports the BACnet communication protocol and has been designed to meet the requirements of the application-specific control profile. For more details, refer to the BTL web site at www.bacnetassociation.org.

Rotary Switches and LEDs

This section provides information about the BCI-C rotary switches and LED displays.

Rotary Switches

There are three rotary switches on the front of the BCI-C device that are used to define a three-digit address when the BCI-C is installed on a BACnet communications network. The three-digit address setting is the BACnet MAC address.

Note: All devices are MSTP masters with valid MAC addresses of 001 to 127 for BACnet.

Figure 1. Setting rotary switches

[Diagram showing rotary switches and their settings before and after adjustment]

Important: Each device on the BACnet/MSTP link must have a unique rotary switch setting, otherwise, communication problems will occur.

[Illustration of a screwdriver being used to set rotary switches]

Note: For details on setting the baud rate, BACnet Device ID, and units of measure, refer to the section, Configuring the BCI-C in the BACnet Communication Interface (BCI-C) Field Kit Installation Guide, RF-SVN02.

LEDs Description, Behavior, and Troubleshooting

There are 15 LEDs on the front of the BCI-C unit. However, LEDs BO1 through BO9 are not used for the BCI-C controller. Figure 2 shows the locations of each LED. The following table provides a description of each LED activity, an indication or troubleshooting tips for each, and any notes.

Figure 2. LED locations

[Diagram showing the locations of LEDs on the BCI-C unit]

BACnet Data Points and Configuration Property Definitions

The BCI-C device allows certain models of Trane chillers with CH530 controls to communicate with BACnet systems and devices using BACnet MS/TP. This section includes information about:

• BACnet protocol implementation conformance statement (PICS)
• Object types: descriptions and configuration (refer to Table 2, p. 12)
• BACnet protocol: data link layers, device address binding, networking options, and character sets
• Object data points and configurations

BACnet Protocol Implementation Conformance Statement (PICS)

Standardized Device Profile (Annex L)

Interoperability Building Blocks (Annex K)

Segmentation Capability

Object Types

BACnet Protocol

Data Link Layer Options

Device Address Binding

Networking Options

Character Sets

Indicates support for multiple characters sets, but does not imply that all character sets are supported simultaneously. Maximum supported string length is 64 bytes (any character set).

Object and Diagnostic Data Points and Corresponding Chiller Models

For quick reference, the following tables are listed and sorted two different ways. Tables 3 through 9 are listed by input/output type and sorted by object identifier. These tables provide the user with the units type for each object type. Table 9, p. 22 is sorted by object name and provides a complete list of object names, types, values/ranges, and descriptions. Not all points are available to the user. The available data points are defined during self-configuration and are dependent on the type of equipment. Listed at the bottom of tables 3 through 8 are specific footnotes that correspond to either specific chiller models or object states that are identified by a larger dot or boldface text.

Note: The last four columns in each table identifies which chiller model corresponds with each object name.

Table 3. Analog Output

(a) Leaving condenser water temperature control.

(b) Hot water control with heat pumps in heating mode.

Table 4. Analog Input

Table 5. Multistate Output

(a) Chiller should be selected for ice making.

Table 6. Multistate Input

(a) Chiller should be selected for ice making.

Table 7. Binary Output

Table 8. Binary Input

Table 9. All Object Types Sorted by Object Name

(Refer to previous tables for detailed descriptions of objects)