Aerospace Temperature Transmitter: Fiber Optic EMI-Immune Sensors for Engine Test and Autoclave Monitoring

Aerospace Temperature Transmitter for Test and Manufacturing

Aerospace work pushes temperature measurement to its extremes: cryogenic fuel systems at one end and composite curing autoclaves at the other, all inside environments full of high-current electrical noise. This case covers engine test stands, environmental test chambers, composite curing and high-voltage avionics benches.

Real Working Condition

• Engine test stand: exhaust and casing temperatures from ambient up to several hundred degrees Celsius, with strong vibration.
• Environmental chamber: controlled ramps spanning roughly −55 °C to +150 °C.
• Composite curing autoclave: about 180 °C at elevated pressure.
• High-voltage avionics bench: dense electromagnetic fields where a metal sensor path would be a liability.

Customer Pain Points

• Electrical noise: power electronics and high-voltage switching corrupted conventional sensor signals.
• Ground loops: the metallic sensor path created circulating currents and offsets.
• Extreme range: a single point can swing from cryogenic to high temperature, defeating narrow-range devices.
• Vibration and transients: engine tests demand fast response without mechanical failure.

Engineering Selection

The lab combined three models. The QW-SLS77 fiber optic temperature transmitter provided measurement immune to electromagnetic interference, with no conductive path into the high-voltage zone. The QW-SLS63 SS316 armored thermocouple / Pt100 covered points needing high accuracy under vibration, and the QW-SLS61 durable high-temperature thermocouple delivered the fast response required for transient engine conditions.

Installation Logic

• The fiber optic probe is routed into the high-voltage zone so that only light — not current — crosses the boundary.
• Armored sheathed sensors are mounted with the correct insertion depth and supported against vibration.
• Each channel is calibrated against a traceable reference before a test campaign.
• Sensor range and sheath material are matched to the specific duty: exhaust, chamber, autoclave or cryogenic line.

Results

Fiber optic sensing removed the noise and grounding problems that metal sensors suffer in high-voltage environments, while armored and fast-response contact probes handled the wide temperature span and vibration of engine testing. The result is trustworthy data across the full test campaign, from cryogenic conditioning to autoclave cure.

Procurement Decision

Confirm the required temperature range per point, the degree of EMI immunity needed, and whether a non-conductive (fiber optic) path is mandatory. Request material and calibration documentation for traceability, verify sheath material compatibility with the exhaust or curing environment, and plan lead time, since aerospace-grade sensors are often made to order.