A p p l i c at i o n B r i e f AB1001
CEL ZigBeeTM/802.15.4 Application Brief Data communication path in HVAC Systems utilizing wireless ZigBee Modules Introduction Building/Factory owners are faced with the physical introduction of new control and monitoring technology in both new and existing buildings in sometimes difficult and remote locations. More and more commercial operations are looking to improve their “green” credentials by addressing excessive energy usage. Industrial Plant Monitoring, redefined as Thermostatic controllers and temperature sensors, can be specifically identified in the following applications:
• HVAC control
• Room temperature sensors • Series receivers • Network coordinators • Fan control • Louvre Motor control • Pump configuration and control
Wireless Technology offers the solution to the difficulty encountered in the installation of new “wired” systems; ZigBee Technology provides the most user friendly environment in which to provide these new services.
Figure 1 Typical internal wireless paths in an Industrial environment
AB1001
The ZigBee Solution The technical specification ~ ZigBee Pro or IEEE 802.15.4? In most cases, the full ZigBee mesh network application (ZigBee Pro) will not be required for proprietary Industrial HVAC Applications. Point-to-Point (P2P) or Point-to-Multipoint (P2MP) capability will probably be the most suitable application for most User requirements. However, some proprietary applications may require small mesh networks of between 10 and 100 nodes; in these HVAC applications the IEEE 802.15.4 Wireless specification will be most appropriate. The ZigBee 2.4 GHz Radios communicate in P2P, P2MP and mesh networks utilizing low power radio transmissions which are reliable in existing RF environments. Buildings, constructed of metal, brick and concrete, can offer challenges which ZigBee radios can overcome by navigation through mesh networks as well as ‘star’ and ‘cluster-tree’ networks.
Figure 2 Examples of Network Topologies
ZigBee Technology Module or IC? For Industrial HVAC applications a ‘module’ rather than an ‘IC’ is often the preferred solution; lack of internal RF engineering design capability and the requirement for rapid time to market being key factors. Often the requirement is a low tech, wire-replacement, application where the ZigBee/802.15.4 radio is not central to the end application. Volumes are in the low to moderate region (5000 to 20,000 units) and pre-designed radios not requiring RF design expertise (and hence time and costs) become the most cost effective solution. ZigBee IC solutions, on the other hand, require in-house (or sub-contracted) experienced wireless engineering teams where system volumes normally exceed >100,000 units per year. Applications tend to be ‘open systems’ that will implement the full ZigBee stack specification and will be price sensitive consumer markets.
AB1001 CEL’s ZigBee Ready Module Solution ~ Matrix ZMXM-400-1 CEL and LS Research (LSR) have formed a joint venture to provide ZigBee-Ready modules; LSR are responsible for the design (both hardware and software) and CEL for manufacturing and marketing of a series of ZigBee modules, including the Matrix Module described below. Matrix Modules offer a miniature, fully integrated transmission solution based on the Texas Instruments CC2430 transceiver IC. The Matrix Module ZMXM-400-1 features ‘Dynamic Power Configuration’ (DPC) which allows the user to drive the module at 10mW when enhanced range is required, or bypass the power amplifier for 1 mW output for low power operation; changing power output is easily implemented in the embedded software.
ZMXM-400-1 Specification
Figure 3 CEL ZMXM-400-1 ZigBee Module
• Based on Texas Instruments chipset CC2430 transceiver: 8kB RAM and 128kB Flash • Power Output ~ 10mW (higher power 100mW version available) • Sensitivity ~-92dBm (typ.) • Low Power operation Receive mode: < 27mA Standby mode : < 5 µA • Data Rate ~ 115.2k baud • Dimensions ~ 0.92” x 1.13”; including integrated antenna (external antenna option available) • Extendable functionality General purpose Digital I/O-17 pins 8 Channel input 12 bit A/D • Certifications FCC Part 15.247 Module Certified (Portable) / IC (Canada EN 300 328 1 Certified / CE Approved
Applications Software LSR Host/Application layer provides a high level interface to the IEE802.15.4 MAC Layer via a serial interface. The LSR software pre-loaded into the Matrix module MCU has sufficient features/power for ‘module-to-module’ communication; details of which can be found on the Matrix Evaluation Kit CD.
Figure 4 LSR Host Application Layer The ZigBee Alliance publishes a set of public application profiles, which define what messages are sent ‘over the air’ for a given application; therefore, devices with the same application profile inter operate end-to-end. However, currently most vendors create manufacturer specific profiles.
AB1001
Application Examples 1. Wireless Industrial HVAC System can be established simply to replace an existing wired system for the communication path.
Figure 5 Typical HVAC Block Diagram
AB1001 2.
Hotel Energy Management Systems allow the hotel operator to ensure that empty rooms are not cooled or heated thus saving energy. A wireless HVAC system consisting of Battery operated thermostats, occupancy detectors and humidity sensors will be easy to install as all units can be placed in a convenient location and are easy to retrofit due to the lack of cabling. The hotel operator can personalize the room settings for regular Clients (according to their recorded profiles) at check-in.
Each HVAC unit can be connected to an energy management controller that adjusts room temperatures based on occupancy information received from the hotel’s management software.
Figure 6 Standard in-room wireless thermostat that can be controlled remotely by an energy management system
Figure 7 HVAC Louvre control unit
Conclusion and Benefits ZigBee Networks are easily retrofitted to accommodate budgets and building schedules; where there is a wired communication connection today there is an opportunity for CEL wireless ZigBee Modules. In most cases a full ZigBee PRO mesh is not required as systems are commonly proprietary; the P2P, P2MP and small mesh applications are normally most appropriate. The estimated cost of design of time and money for a ZigBee solution can be briefly summarized as follows:
• Hardware ~ $20-$30K (Radio/ analog design is difficult and costly) • Software ~ $85K (Develop, implement, and maintain ZigBee stack) • Certification ~ $11-$32K (Each radio implementation requires certification)
CEL modules reduce total system time to Market
• CEL’s evaluation kit enables network prototyping in days not months ~ In house design can take many months • CEL’s ZigBee modules get you to market quicker with proven cost-effective solutions! • Radio design is: part engineering and part art ~ Design re-spins will add time and engineering resources to get radio “right” ~ CEL’s modules are already in production • Failing FCC / CE certification can add months of time and cost to in house design ~ CEL’s modules have already been certified
AB1001
Supplementary Information
CEL IEEE 802.15.4/ZigBee Transceiver Modules CEL modules provide a fully integrated, easy-to-use solution for your IEEE 802.15.4 networks. Ideal for remote sensing, AMR/AMI, home and building automation, and security applications, they feature low power consumption, long range and integrated antennas. Qualified and certified, CEL modules are the result of broad applications knowledge and over 45 years of product development experience. They combine industry-leading transceiver ICs with high performance Power Amplifiers, RFIC switches and other components from CEL‘s long-time marketing partner, NEC Electronics.
MCU
MODULE
NEW FreeStar Pro
Transceiver Chipset
FreeStar
Apex
Apex LT
Matrix 10mW
Matrix 100mW
Freescale™ MC13224 32 bit, ARM7
Freescale MC13192 8 bit, HCS08
Ember™ EM250 16 bit, XAP2b
Ember EM260 Network processor
TI™ CC2430 8 bit, 8051
TI CC2430 8 bit, 8051
32MHz
40MHz
12 MHz
n /a
32 MHz
32 MHz
46
8
17
n /a
17
17
Mesh, Point-to-Point, Point-to-Multipoint
Mesh, Point-to-Point, Point-to-Multipoint
Mesh
Mesh
Mesh, Point-to-Point, Point-to-Multipoint
Mesh, Point-to-Point, Point-to-Multipoint
Freescale BeeStack™
LSR STAR Protocol BeeStack™
Znet Pro® 3.1 (ZigBee Pro Certfied)
Znet Pro ® 3.1 (ZigBee Pro Certfied)
LSR STAR Protocol Z-Stack™
LSR STAR Protocol Z-Stack™
Fmax
NETWORK
Inputs / Outputs Network Software / ZigBee Stack Tx Power Output PERFORMANCE
Rx Sensitivity
+20dBm
+20dBm
+20 dBm
+20 dBm
+10 dBm
+20d Bm
– 100dBm
–92dBm
–97 dBm
– 97 dBm
–92 dBm
–92 dBm
Range
> 4000 ft
4000 ft
> 4000 ft
> 4000 ft
2000 ft
4000 ft
Vcc
2.0 – 3.6V
2.4 – 3.6V
2.1 – 3.6V
2.1 – 3.6V
2.1 –3.6 V
2.1 – 3.6V
Rx Current
30mA
42mA
37 mA
37 mA
27 mA
27 mA
Tx Current
193mA
150mA
170 mA
170 mA
50 mA
130 mA
Standby Current Dimensions
1.1µA
5µA
5 µA
5 µA
5 µA
5 µA
25 x 36 mm
25 x 36mm
25 x 33 mm
25 x 33 mm
23 x 29 mm
23 x 31 mm
PART NO.
ZFSM-201-1
ZFSM-101-1
ZAXM-201-1
ZALM-301-1
ZMXM-400-1
ZMXM-401-1
EVAL KIT
ZFSM-201-KIT-1
ZFSM-101-KIT-1
ZAXM-201-KIT-1
ZAXM-201-KIT-1
ZMXM-400-KIT-2
ZMXM-401-KIT-1
4590 Patrick Henry Drive, Santa Clara, CA 95054 (408) 919-2500 www.cel.com CL-627B 10.28.08
Information and data presented here is subject to change without notice. California Eastern Laboratories assumes no responsibility for the use of any circuits described herein and makes no representations or warranties, expressed or implied, that such circuits are free from patent infringement. © California Eastern Laboratories 11/08
4590 Patrick Henry Drive, Santa Clara, CA 95054-1817 Tel. 408-919-2500
FAX 408-988-0279 www.cel.com
