290 likes | 383 Views
SDDEC1004 High Speed Wired Data Collection. Honeywell Bob Dearth Michael Retzler Brad Lucht ISU Prof. Zhengdao Wang Zachary Coffin, Cpr E Radell Young, E E William Zimmerman, E E*. Requirements / Specification Problem / Need Statement.
E N D
SDDEC1004High Speed Wired Data Collection Honeywell Bob Dearth Michael Retzler Brad Lucht ISU Prof. Zhengdao Wang Zachary Coffin, Cpr E Radell Young, E E William Zimmerman, E E*
Requirements / SpecificationProblem / Need Statement • Honeywell’s Kansas City Plant needs a method to collect experimental data very quickly over a distance of 300 feet. All previous designs are now too slow and error-prone to collect useful data.
Requirements/SpecificationConcept Description • Transmitter and Receiver • Commercial Off-the-Shelf Components • Speed requirements • Cost constraints • Availability • Cat-5e • Frequency Response • Availability and Cost • Onboard Battery
Requirements/SpecificationOperating Environment • Equipment shall be used indoors in a regulated testing environment. • Transmitter shall be housed in a larger device, in a cavity no larger than 3x3x1/2 inches. • Nature of experiments inhibits wireless communication. • Data is to be retrieved on a Windows XP machine.
Requirements/SpecificationUser Interface Description • Data shall be made available in a table format on a Windows XP computer • There may be an optional power indicator LED on the transmitter board
Requirements/SpecificationFunctional Requirements • Convert four analog voltage signals from provided piezoelectric sensors to 8-bit digital signals at a minimum rate of 2 million samples per second • Data collection and transmission must start from a time approximately T-4 second, and end no earlier than T-5us • System shall use wired connection • Maximum Voltage Supply 24V DC • Minimize error
Requirements/SpecificationNon-Functional Requirements • Budget $100 per transmitter • Transmitting device shall be no larger than 3x3x½ inches in volume
Requirements/SpecificationMarket / Literature Survey • Chipset optimized for performance at target price • All-in-one chips too expensive and too high latency • Cable specified for availability and cost considerations
Requirements/SpecificationDeliverables • Chipset meeting all design requirements (cost, size, performance) • Schematic has been created in Cadence • Footprints for some chips were not provided in datasheets – this delayed PCB generation
Project Plan:Resource Requirements • Manufacturing equipment to produce hundreds of transmitter boards • Sensors and appropriate biasing circuitry as analog input sources • Windows XP data capture environment
Project Plan:Risks • Loss of team member – MazdiMasud • New team member – Bill Zimmerman • Signal loss too great • Specify more robust cable – Shielded Cat-6 • On-board latency too great • Add clocked register between multiplexers and LVDS
System DesignSystem Requirements / Analysis • PCB layout to connect chips as necessary • No less than 3.3V energy source • A combination of several button cell batteries may provide a more cost-effective solution than standard 9V cells
System DesignFunctional Decomposition • Transmitter board • Accepts four voltage signals (current version takes a range of -150 to +150 Volts, as specified by piezo sensor) • Applies 1-bit odd parity to each channel • Transmits over four channels (three data, one clock, eight conductors) in LVDS • Receiver board • Regenerates clock signal • Decodes LVDS data and sends to USB UART • Windows XP • Aligns data samples to satisfy parity check
Detailed DesignHW/SW Specifications – Chipset • Measurement Specialties, - Inc. LDT 1-028K/L(Piezo, 4x) • Texas Instruments - TPS76918DBVR (Voltage Regulator, 2x) • Texas Instruments - TPS76933DBVR (Voltage Regulator, 2x) • Texas Instruments - ADS931E (AtoD, 4x) • Texas Instruments - CD74AC280M96 (Parity, 4x) • Texas Instruments - ADG706BRUZ (MUX, 3x) • ECS Inc. - ECS-240-12-4X (24MHz Crystal) • Texas Instruments - CDCE913PW (Clock Generator, 2x) • Texas Instruments - CD74HCT163E (Counter) • National Semiconductor - DS92LV040ATLQA (LVDS Transceiver, 2x) • ST Ericsson - ISP1506ABS (USB Transceiver) • Fairchild Semiconductor - 74VHC04MX (Inverters) • Texas Instruments - SN74LV27ADR (NOR gates)
Detailed DesignI/O Specifications • The individual sample bits are transmitted in the following 12-bit pattern: • Where 8-bit samples A through D consist of bits 0 through 7 and parity bit ‘P’.
Detailed DesignUser Interface Specification • Once the transmitter board is powered it will continuously transmit data – no interaction required. • Data may be collected from the UART as desired
Detailed DesignTest Plan • Testing specifications received from Honeywell • Input square waves of frequencies up to 1MHz • Signal input to LVDS transmitter must not waver during one clock period due to MUX propagation delay • If it does, signal buffer will be required, increasing latency, cost, size, and requiring a different PCB
Detailed DesignSimulation / Prototyping • Complexity of the system prevented simulation • Prototype construction is taking longer than anticipated
PrototypeBuild • PCB design could not be finalized before receiving chipset • Some datasheets did not include device dimensions • Second loss of team member reduced available man-hours dedicated to project • Obtained chipset, sensors, cable, and final schematic
PrototypeTest Results • Typical sensors (supplied by Honeywell) deliver ±150V • 300ft of Cat-5e cable was tested for crosstalk and signal degradation • Signal loss measured as -10dB at 24MHz • Cross-talk measured minimal
PrototypeTest Results Piezosensor test results Voltage measured at 50 attenuation factor Cat-5 Cable test results Frequency response similar for distinct pairs Crosstalk very low for all pairs
Project ClosureConclusions / Lessons Learned • Be Proactive • Team members may be motivated by the activities of others • Follow a Design Process • After a process is selected tasks can more easily be distributed amongst team members • Stay Positive • Perform to the best of your abilities
Project ClosureFuture Work • PCB must be completed based on measurements of chip dimensions • Chips and interface jacks must then be soldered • Software to decode data stream • Align data samples to satisfy parity check
Project SuccessInnovation • Multiple transmission methods were investigated in order to determine the best method of achieving success within constraints set by Honeywell. • Methods considered include: • QAM and coaxial cable • Simple Low Voltage Differential Signaling (LVDS) and twisted pairs (category-5) cable • LVDS Multi Level Transmitting 4-levels (MLT-4) and Non Return to Zero Inverting (NRZ-I), again with cat-5 cable