Wireless User Interface for Variable Frequency Drives Team 168 Alex Shuster (EE) Michael Kloter (EE) Christopher Perugini (EE) Kevin Wei (EngPhys - EE) Sponsor: Lenze Advisor: Professor John Chandy

Outline Lenze Objectives and Deliverables Research and Proposed Solution Hardware Network Topology Programming Timeline Budget Future Work

Lenze Provide Motor Control Solutions Automotive Construction Robotics Manufacturing and Packaging Variable Frequency Drives Speed and control system for AC motor

Objective - Deliverables Current Problem Manually Set Parameters Limited Accessibility Long Individual VFD Programming and Reprogramming Objective Develop a wireless interface on the VFDs Maximize the transmission distance Monitor and transmit to multiple VFDs at once Able to operate in an industrial environment

Researched and Proposed Solution Researched various wireless communication options such as Wi-Fi, Bluetooth, and ZigBee Wireless Communication Choice: ZigBee m / node Low complexity, cost, power consumption Low to medium data rate Operational in an industrial environment

Technical Solution Physical LayerProtocol RS-485Modbus Ethernet Phy802.3 CANCANOpen

Hardware Develop test application to validate wireless implementation

Firmware and Debug ONLY Current Hardware Components Sparkfun ATMEGA128RFA1 Sparkfun RS-485 Breakout

Hardware Configuration

ZigBee Lightweight Mesh Basic data services (send and receive data) Acknowledgements Routing Basic security Power management of the radio transceiver Network management (discovery, joining, commissioning, etc) Advanced network operation scenarios (sleeping routers, parent- child relationship, data delivery to the sleeping nodes, etc) Retries to send data in case of failures Defining message payload format Advanced security Power management of the MCU Interfacing hardware peripherals (ADC, PWM, EEPROM, etc )

Transceiver Schemes Option One: FIFO Byte by byte The USART will receive 8 bits, then pass that to a buffer. This buffer vector will be inserted into the ZigBee frame payload and the entire frame will be passed to the ZigBee radio frame buffer to await transmission Option Two: FIFO Message The USART will receive 8 bits, then pass that to a buffer. The MCU will wait for a full modbus message to be received 8 bits at a time and save in a message buffer This message buffer will be inserted into the ZigBee frame payload and the entire frame will be passed to the ZigBee radio frame buffer to await transmission

Programming Options Predefined Buffer Size Transmits when buffer filled Variable Buffer Size Transmits when timer triggered Real Time Transmission Transmit data as received

Predefined Buffer Size Previous Method: 8 Byte Buffer Size Would receive data bytes from the computer and fill a buffer array of size 8, and then transmit all of the data. Downside The Techlink software sends varying message sizes including up to 13 bytes. The time required to transmit the full buffer can conflict with new incoming data being stored.

Variable Buffer Size More Complicated Method Makes use of the Modbus protocol A timer is triggered if 3.5 characters go by without data, this indicates that a complete message has been sent. Once the timer is triggered, the buffer will be sent to the VFD. Downside More complicated, and transmission times can interfere with receiving new data.

Transmission as Data is Received Easier method As each data byte comes in from the computer, it is transmitted to the VFD. Downside Greater overhead delays when the data is transmitted over ZigBee due to packetization.

Programming Choice Method Chosen: As Received This allows for Lenze to adapt the code to other applications. Will not restrict the use for future products.

Budget Lenze Grant: $1000 ProductQuantityUnit PricePrice Design Estimates In System Programmer1$35.36 Single Chip MCU and ZigBee 3$9.75$29.25 RS-485 to UART Transceiver 3$2.70$8.10 ZigBee Development Kit1$ Misc. Supplies$ Total:$290.71

Timeline

Future Work ZigBee PCB Antenna Researched PCB Antenna Designs Easy to tune Reduces Costs MCU Integration Via VFD’s RS-485 Option Module Eliminate External Hardware Wireless Upgrade Package

Questions