Project Number: P15452

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Multidisciplinary Senior Design Conference Kate Gleason College of Engineering Rochester Institute of Technology Rochester, New York 14623 Project Number: P15452 DATA ACQUISITION DEVICE Kyle Smith

1 Multidisciplinary Senior Design Conference Kate Gleason College of Engineering Rochester Institute of Technology Rochester, New York Project Number: P15452 DATA ACQUISITION DEVICE Kyle Smith Electrical Engineer Stephen Opdyke Computer Engineer Lucas Sychtysz Mechanical Engineer Louis Amezquita Electrical Engineer ABSTRACT The purpose of this project is to create a universal data acquisition devise capable of operation within a harsh environment of a Dresser Rand Compressor. The devise must be capable of recording analog voltages from a variety of sensors with sample rate between.1 Hz to 10kHz. The data acquisition device must be easy to use, where the data retrieval and battery charging is done by mini USB. The devise is capable of over 8 hours of operation. In order to fulfill harsh environment requirement robust and watertight casing and connecter were incorporated. Due to early success, the team has designed a version 2 of the DAQ device where improvements were incorporated. INTRODUCTION The data acquisition device is needed for the continuation of health monitoring research of a Dresser Rand Compressor. A compressor has many harsh environments and challenging area of access, where a small, robust, and easy to use DAQ device is needed to measure vibrations and temperatures. Being able to record data will enable the user to monitor the health of the compressor. Other applications of the DAQ device can be used such a UAV. Two other Senior Design Teams have attempted to fulfill this team objective, but fell short. P14452 Team wasn t able to develop a fully functioning device capable of meeting all of the customer requirements. The P13453 Team was successful overall, but their device s measurements were not in sync with the time stamps. DESIGN PROCESS Customer Requirements The first step in beginning the design process was encapsulating all of the requirements that our customer had, Dresser Rand and Dr. K, so that the team could obtain an overall picture of what the product needed to have. Through various discussions with Dr. K a set let of requirements were created that evolved over the time we were working on the project. The most important requirement is that the data must be easily extractable from the device. If it takes a while to get the data off of the device than the device would be more of a hassle than what its worth. This can be done either by physically removing a storage device off of the DAQ or through serial communication. The amount of storage on the device is also essential. The storage size must be capable of holding data at the maximum sample rate of 10kHz for around 2 hours. The product must also be securely mounted on the piece of equipment that it is collecting data from. Accuracy will also be ensured for analog voltage sampling by benchmarking our product against a store bought DAQ. Once the data is off of the device, the extracted data should also have accurate time stampings for the measurements. Being that our device will be collecting data wirelessly it must also ensure that the device can power the sensors that it is using to collect the data. These requirements that I Copyright 2008 Rochester Institute of Technology

Proceedings of the Multidisciplinary Senior Design Conference Page 2 mentioned must be considered to be the highest of importance but some other requirements can be seen in Figure 1 below.

Every engineering requirement matches up with a specific customer requirement where at the start of MSD estimated marginal and ideal values were brainstormed for a functioning product.

2 Proceedings of the Multidisciplinary Senior Design Conference Page 2 mentioned must be considered to be the highest of importance but some other requirements can be seen in Figure 1 below. Figure 1: Customer Requirements Engineering Requirements The customer requirements were analyzed to develop a prioritized list for engineering requirements. Every engineering requirement matches up with a specific customer requirement where at the start of MSD estimated marginal and ideal values were brainstormed for a functioning product. The highest rated customer requirement is the ability to extract data easily from the device. Engineering requirements can be tagged to that by measuring the amount of time it takes for the device to extract data as well as the means of the data extraction. As for having enough storage size to hold the data at a maximum sample rate, the SD card size must be taken into account. The device must also be accurate so there must be testing to see what the sampling resolution should be as well as the error in that resolution. As seen from the figure below there are more engineering requirements that can be tied directly to which customer requirements based on the source CR#. Figure 2: Engineering Requirements Case The Hammond Manufacturing (1554B2GYCL) Enclosure was chosen to house all the components of the DAQ. This case dimensions are 2.6 x 2.6 x 1.6 which fulfills the requirement of modularity. It has a tongue and grove construction between the casketed lid and the lower part to protect against oil, dust and water. A clear lid shows the user visibility of the LED, which shows what function the DAQ is currently in. The case has two mounting holes located outside the gasket seal. The case is machined per print in order for the button, 3 male mini XLR connector, and a female micro USB can be installed onto the casing. The bottom inside surface of the case must be machined flat, due to stand offs. Project P15452

Proceedings of the Multi-Disciplinary Senior Design Conference Page 3 Figure 3: Finished Case Mini XLR Connectors The Rean Mini XLR Connectors (RT3MP and RT3FC-B-W) were chosen for this DAQ.

The male Mini XLR provides a water tight seal and even protects the connector in an unmated condition. These connectors will connect to accelerometers within the compressor and testing environments.

Mini USB provides capabilities of transferring data from the DAQ to PC using mini USB and it provides charging capabilities.

3 Proceedings of the Multi-Disciplinary Senior Design Conference Page 3 Figure 3: Finished Case Mini XLR Connectors The Rean Mini XLR Connectors (RT3MP and RT3FC-B-W) were chosen for this DAQ. These connectors have a rugged locking mechanism which provides secure connections in harsh environments. Can be disconnected only by pressing the unlocking tab. The male Mini XLR provides a water tight seal and even protects the connector in an unmated condition. These connectors will connect to accelerometers within the compressor and testing environments. Mini USB Connector The Amphenol Type Mini B Female USB (MUSBB151M0) was chosen on the DAQ. Mini USB provides capabilities of transferring data from the DAQ to PC using mini USB and it provides charging capabilities. The female USB panel is environmentally sealed to the case with 2 screws creating seal with gasket. This connector is water resistant in mated and unmated conditions. Button The Grayhill Push Button Switch (30-203) was chosen for the DAQ. The button is front panel mounted and is provides sealing. Button is easy to push and different button command can be given to change the mode of the DAQ. Light Logic The DAQ gives the user visibility of what mode it is depending on the color of the LED. Yellow-USB ready Purple-Ready over USB Green-Idle Red/yellow-collecting data going to USB Blue-error Software The SD card was a fairly easy design choice, the micro controller software can only currently support up to 4GB cards, and the price difference between 4GB and 8GB cards is pretty negligible. Most cards can also support SPI mode for data transfer as well, so any off the shelf SD card at least 4GB will work fine. A FAT file system was chosen to be put on the SD card this way data on it could be accessed by a normal operating system on any household computer. The micro controller stores the FAT file data onto the SD card using an SPI bus. It also interfaces the SD card to a computer via a USB port on the device. Copyright 2008 Rochester Institute of Technology

Proceedings of the Multidisciplinary Senior Design Conference Page 4 Microcontroller The microcontroller we chose to use is the LPC1549 manufactured by NXP.

4 Proceedings of the Multidisciplinary Senior Design Conference Page 4 Microcontroller The microcontroller we chose to use is the LPC1549 manufactured by NXP. This is an ARM Cortex M3 processor that has a 48 pin configuration and all the required features we needed for our design. It features two SPI buses, one that we use to communicate with the sensors and the other we use to write data to the SD card. It also has full speed USB support that we used for file transfer onto the PC. The M3 is a bit faster than what was needed for this project, but the power usage did not increase substantially from an M0+ to the M3 we chose and the M0+ we originally planned on using was hard to get development boards for. We ended up with a slightly faster processor than we intended but it had all the features we needed and we ended up using every GPIO pin on the processor anyways.. Power Management To power the DAQ a 1000 ma Li-po battery will be used. The power supply will than convert the voltage from the Li-po battery which ranges from 3.2 to 3.7v to a 5v supply. The power supply operates at 100mA where the IC sees 84% efficiency. The ripple voltage for the circuit under load is 50 mv and the circuit can be seen in Figure 4 below. Figure 4: Power Supply Circuit The battery charging is done using an U1001. It s tested for 890mA peak charging current. The circuit has a 4.2V charge voltage limit. The complete charge cycle for the 1000mA battery is 2 hours and 20 minutes from the battery being completely dead at 3V. The circuit can be seen below. Figure 5: Battery Charging Circuit Analog Input System The analog input system has 3 stages. The first is a combination of a 40 khz cutoff first order low-pass filter, and resistor divider to divide an input signal range of 0-5V to the ADC input range of V. The second stage is an AD712 analog switch, which is software configurable per channel to enable an additional resistor divider to expand the input range to V at the expense of resolution. The third stage is a 4-channel AD8608 low-noise op-amp configured as a buffer to convert the high-impedance input signal into a low impedance source to accurately drive the AD7682 ADC with very low offset. The ADC is 16-bit and has 4 inputs, one for each signal, and the fourth channel measuring the sensor power output voltage. The ADC transfers samples from these 4 channels over the digital SPI bus to the microcontroller on the digital board. All analog input components are powered through a 5V LT1761 linear low dropout voltage regulator (LDO), which supplies clean power, and is powered by a relatively noisy 5.5V supply from a boost converter on the digital board. Project P15452

Proceedings of the Multi-Disciplinary Senior Design Conference Page 5 Figure 6: Analog Input Circuit Sensor Power System The sensor power system is based on a core of an LT3494 boost converter, which

The LT3494 has a low output ripple of <6mV, in order to not cause ripple in the sensor output signals.

5 Proceedings of the Multi-Disciplinary Senior Design Conference Page 5 Figure 6: Analog Input Circuit Sensor Power System The sensor power system is based on a core of an LT3494 boost converter, which has an output proportional to a controllable reference voltage, which is provided by the microcontroller. The LT3494 has a low output ripple of <6mV, in order to not cause ripple in the sensor output signals. The converter can also source up to 25mA at any voltage from 5V to 24V to power a wide variety of sensors. PCB Fabrication and Assembly The PCBs were designed using the open source KiCad electrical design software. This software was used to draw up schematics, then layout the board and generate the industry standard gerber file outputs for fabrication. These files were sent to OshPark for fabrication. When the boards were received, they were solder pasted and populated by hand, and then passed through a reflow oven to complete the assembly. The finished boards were mounted together with standoffs, and soldered to each other and to the mini-xlr connectors with jumper wires. Figure 7: Overall PCB Layout a) Analog Board b) Digital Board Copyright 2008 Rochester Institute of Technology

Proceedings of the Multidisciplinary Senior Design Conference Page 6 RESULTS Function Generator Test A function generator test was performed where the P15452 DAQ was compared to the 24 bit National

They were plotted on top of each other to check for accuracy. The result showed that P15452 DAQ is capable of recording data accurately as the Ni DAQ.

Vibration Test A vibration test was performed where an accelerometer was attached to a shaker table and a frequency of 5,50, and 500 Hertz was applied.

Data was recorded and exported in text file where the data analyzed by the FFT function provided by Dr.Kolodziej. Results of the FFT analysis for both devices were plotted on top of each other.

Version 2 Improvements The Revision one of the DAQ was a huge success. It is fully functional and fulfilled the customer requirements early in MSD II.

6 Proceedings of the Multidisciplinary Senior Design Conference Page 6 RESULTS Function Generator Test A function generator test was performed where the P15452 DAQ was compared to the 24 bit National Instrument DAQ. A.5,5,50,500,5000hz sine wave created by the function generator and was recorded by the two DAQs. Fourier Transfer Function Matlab code was run on the data collected from the two DAQs. They were plotted on top of each other to check for accuracy. The result showed that P15452 DAQ is capable of recording data accurately as the Ni DAQ. Figures 8,9,10,11,12: FFT of NI and P15452 DAQ for.5, 5, 50, 500 and 5000 Hertz. Vibration Test A vibration test was performed where an accelerometer was attached to a shaker table and a frequency of 5,50, and 500 Hertz was applied. The accelerometer was connected to the 24 bit NI DAQ and P15452 DAQ. Data was recorded for 10 seconds at the same time for both devices. Data was recorded and exported in text file where the data analyzed by the FFT function provided by Dr.Kolodziej. Results of the FFT analysis for both devices were plotted on top of each other. Result shows that both devices accurately measured the correct frequency and results obtained were expected. Figures 8,9,10. FFT of NI and P15452 DAQ for 5, 50, 500 Hertz. Version 2 Improvements The Revision one of the DAQ was a huge success. It is fully functional and fulfilled the customer requirements early in MSD II. With extra time left it was decided to build two new DAQ with improvement features. The casing, connectors, and buttons were kept the same due to satisfactory performance on Revision 2. No additional software is needed for the new DAQ s, both DAQs use the same software. Improvement in Revision 2 included on board layout changes to reduce interference and improve performance. New components allow the DAQ to record 3 channels at 10kHz at the same time. A RAM buffer was implemented in Revision 1 in order to complete the requirement of 10kHz at 3 channels. Project P15452

7 Proceedings of the Multi-Disciplinary Senior Design Conference Page 7 Cost The cost of the DAQ is relatively cheap. The bill of materials cost is $ Non Surface Mount Device costs is $73.80 which comprises of the case, connectors, button, battery, and micro SD card. Surface Mounts Device components totaled of $54.45, which included all electrical components that were mounted on the PCB board. These cost are for all the material for a single DAQ. BOM costs will decreases as more DAQ may be built. Assembly costs and software maintenance will incur additional costs, but exact amount is unknown. An estimation of the total cost may total around $300. Discussion Benchmarking testing confirms that the P15452 DAQ is capable of accurately recording data to the same quality as market DAQ devices such as the 24 bit NI-DAQ. Testing above shows that P15452 DAQ and the NI DAQ have identical FFT at the required frequency. The ability to attach the P15452 DAQ in tight and harsh conditions are features that a lab setting DAQ cannot provide. There are production capabilities of this device. A build of materials and assembly instructions will be provided in order for future manufacturing. CONCLUSIONS Overall the project has had great results and fully satisfied the customer. This is the first project of its kind to be 100% completed and satisfied all of the customer requirements, even low priority requirements were fulfilled. The case selection was the best it can be, because the size was optimal and clear cover feature, water tight seal, and mounting capabilities. The same case was chosen again for revision 2. The ability to charge and transfer data by USB prevents the user from opening the case to retrieve the micro SD card or access the charging port. Robust and water tight connector ensure long lasting durability. ACKNOWLEDGMENTS Mr. Bill Nowak Dr. Jason Kolodziej Copyright 2008 Rochester Institute of Technology

8 Proceedings of the Multidisciplinary Senior Design Conference Page 8 Project P15452

Final Presentation P14452

Final Presentation P14452 Overview MSDI Review Customer Needs Requirements Functional Decomposition Concept Selection Detailed Design MSDII Detailed Design Revisited Build Test Reflect What Remains Lessons