SPX Data Acquisition

SUBSYSTEMS DESIGN REVIEW

John DongDavid HallerAdam JohnsonThomas KlabenLuke Kranz

Presentation Agenda • Phase Objective Statement 3 minutes• Finalized Concept Selection 4 minutes• Subsystem Schematics 10 minutes• Feasibility Studies 5 minutes• Bill of Materials/Budget 5 minutes• Component Procurement 3 minutes• Component Testing/Spec Validation 5 minutes• Risk Assessment/Mitigation 5 minutes• Next Phase Project Plan 5 minutes• Questions 15 minutes

Phase Objective StatementOverall Objective:

◦ To provide SPX with a telemetry system capable of transmitting strain data from gauges attached to an operating impeller, to a user interface of our choice.

Previous Phase:◦ Laid out overall system with the primary function of wireless strain data calculation and transmission◦ Began feasibility studies and concept development, narrowed down to three designs

Subsystems Design:◦ Research and acquisition of components needed to meet our overall objective ◦ Several studies to test the feasibility of our design◦ Selecting our primary design from those generated in the previous phase

Finalized Concept Selection

• Strain Measurement: 1D Strain Gauge

• Gauge Mounting: Adhesive• Water-proofing: Liquid Tape• Wire Handling: Wire Tube• Data Transmission: V-Link LXRS• Data Collection: V-Link LXRS• Power: Rechargeable Battery

System Requirements/Subsystems Mapping

Subsystem Schematics

Strain .CSV

Strain Gauge

-Waterproofing-Wiring-Blade Attachment

Transmitter

-Waterproofing-Wiring-Batteries-Shielding

Receiver

-Power source

Software

-Display Real Time Data-Save to .csv format file

Transmitter Subsystem- V-Link® -LXRS®

Preliminary Decision to use Lord Microstrain V-Link® -LXRS®

Benefits: All in one system

1. 4 differential inputs

2. Built in rechargeable battery

3. Long transmission range

4. Amplifier, filter, and 16 bit ADC for each differential channel

5. 4Mb Internal memory

6. Supplied with software and logging suite

7. Expandable nodal system

Transmitter Subsystem Diagrams

Transmitter Subsystem Feasibility

Feasibility:

Power: Battery=650mAh, Draw from gauges 42.694~43mA(from above at 128Hz, but we could also use 256Hz and stay under 50mA supply limit to gauges). Assume total current 65mA. 650mAh/65mA=10 hours of battery life. Assume 8 to account for not being able to fully drain the battery. That’s 8 hours of continuous logging and use, where our scenario is about 2 hours active use over an 8 hour day. This meets feasibility for power.

Range: from data sheet 70m to 2km with line of sight. We need approximately 10m.

Channels: 4 differential channels with Op-Amp, filter, and 16 bit ADC for each channel. We need 4 strain gauges. This meets our requirements and is scalable by just adding more nodes.

Storage: 4Mbytes on board (2,000,000 points). From prior feasibility this is more than we need, and this is being transmitted and not permanently stored.

Sampling Rate: We need minimum 100Hz, can do 32Hz-10kHz.

Acceleration limits: Limit is 500g, other feasibility analysis shows this is more than we need.

Environmental: IP65/66 available (able to protect against water-powerful water jets). We only need splash protection, but are considering a water resistant case for additional water protection and easy of mounting.

Transmitter Subsystem Power

Transmitter System Specifications

Feasibility – Gauge Application and Removal

Questions:◦ Can commercially available strain gauges be used for multiple impeller tests?

◦ What adhesive will allow for easy removal, and will it affect strain readings?

◦ What solvent can remove this adhesive without damaging the gauge?

Research:◦ Multiple Tests – answered by previous study: choose higher NEMA rating than required

◦ Adhesive – M-Bond AE-10: highly resistant to moisture and chemicals, cures at room temperature, water-resistant coating, elongation capability up to 5%

◦ Solvent – many only work on non-cured adhesives, further research will be needed

Testing:◦ Not yet completed due to lead times on components

◦ Simple test plans written to confirm research and answer questions

Conclusions:◦ Research says that strain gauges can survive for more than one test, and adhering to an impeller underwater should not be an issue

◦ Further research must be completed on methods of removal and re-use for strain gauges

◦ Testing should confirm all research

Feasibility – Waterproof Connections

Feasibility – Wire and Transmitter Protection

Transmitter Protection – Acrylic cube sealed with silicone -Must be waterproof; accidental drops into the test tank could ruin a ~$1000 piece of equipment -To test, build case and place in tank of water for 10 seconds. If no water has entered the case, the case passes If any water has entered the case, the case fails, as the transmitter is no longer protected.

-Counterweights may be added to shaft to reduce vibration.

Wire Protection – Shielded wires running along impeller shaft -3 wires are run through a shielded and grounded casing – Sensor +, Sensor-, and ground. -The shielded casing prevents interference from other electrical equipment in the lab, and the larger wires will be easier to secure, reducing the amount of “tugging” on the strain gauges, providing a more accurate reading.

Bill of Materials/Budget

Component ProcurementItem Company Part # Quantity Total Price Remaining Budget

1kΩ Strain Gauge Omega SGT-1A/1000-TY43 5 31.70 4968.30Liquid Electrical Tape Home Depot LTB-400 1 5.99 4962.31

V-Link LXRS Lord MicroStrain 6312-1000 1 2030.00 2932.31

Component Testing/Spec ValidationStrain Gauges

Clamp test piece to perform tests. Affix strain gauges a measured distance from the free end of the test piece. Apply a load on the end of the clamped test piece (cantilevered beam model) Calculate stress and strain as follows: Determine moment using singularity functions: q(x) = P<x>-1

M(x) = P<x>1

Where x is the distance from the free end of the test sample Stress Calculations: σ = -MC/I Where C is one half of the beam thickness and I = (1/12)bh3

Strain Calculations: ε = σ/E = -MC/EI Where E is Young’s Modulus If the calculations and the actual experiment yield results within 5%, this shows our gauge placement and calibrations to be accurate.

Component Testing/Spec ValidationWaterproofing Gauges

-Affix strain gauges to test sample -Place a known load on the test sample, record measurement -Apply waterproof coating to strain gauge and exposed connections -Place the same known load on the test sample. If strain measurement is within 2% of the original, then the waterproof covering is determined to not affect the strain reading.

-Submerge testing rig in salt water -Place the same known load on the test sample. If strain measurement is within 2% of the original, then the waterproof covering is determined to be effective.

Risk Assessment – Updated Risks

Risk Assessment – Risk MitigationTelemetry Life Cycle:• Rotational Forces?

• Max Acceleration Limit Spec: 500g

• Max Rotational speed of Shaft: 150 RPM • Shaft Radius ~= 1 in = 0.0254 m• Transmitter Dimensions: 74 mm x 79 mm x 21 mm• Max acceleration at outer surface of transmitter

• 0.69 g < 500 g

Risk Assessment – Risk MitigationTelemetry Life Cycle:• Can Transmitter Stay Dry?

• Transmitters will be mounted above the tank water level• There may be chance that transmitter may get splashed during high energy mixing

• Transmitter will be mounted to shaft via a plastic case which will also protect it from liquids

Next Phase Project Plan – Gantt Chart

Questions