Project Description
TWe want to use thermocouples to measure temperatures on the engine because of their very large temperature range. However, the signal they output is very weak which makes it hard to measure accurately. Spidey Sense is a board designed to measure thermocouples for DAQ, but so far we have not been able to get acceptable performance / accuracy out of two revisions.
The goal of revision 3 is to use a daughter board to perform the actual thermocouple signal conditioning. The daughter board may give an amplified analog output, which can then be directly fed into the NI box, or it may give a digital signal which would require an external microcontroller to process and feed into the DAQ computer.
Requirements
Capable of measuring at least 1 K-type thermocouple at 10 Hz
Accuracy of within 5 C (cold junction compensation is likely required for this)
Able to get data onto Omnibus
Able to measure 8 total thermocouples when copies are mounted into the DAQ briefcase using the hole pattern drilled for revision 2.
Scope
The scope involves sourcing an acceptable COTS thermocouple conditioner and potentially designing a system based around a microcontroller to get the data onto Omnibus. Designing the amplification circuit ourselves is explicitly not in scope (revision 2 tried this and had significant issues).
Required Documentation
Design doc
Design explanation of why the specific COTS module was selected
Deliverables Timeline
Oct 9: COTS module selected and purchased, design explanation complete.
Oct 23: Tech demo of using the COTS module to read a thermocouple.
If additional conversion circuitry is required:
Oct 30: Schematic for conversion board approved.
Nov 13: PCB ordered.
Nov 27: Fit test of mounting PCB and COTS module(s) into the DAQ briefcase.
Dec 4: Tech demo of using the PCB to read a thermocouple.
Jan 15: Integration test of reading thermocouple data onto Omnibus from within the DAQ briefcase.
Jan 29: Final integration test of support for at least 4 thermocouples added to DAQ briefcase.
If no additional circuitry is required:
Nov 13: Fit test of mounting COTS module(s) into the DAQ briefcase.
Nov 27: Final integration test of support for at least 4 thermocouples added to DAQ briefcase.