Our pressure transducers feature digitally compensated electronics that are environmentally protected within a sealed enclosure. The transducers are highly accurate over a broad temperature range, resisting the effects of wide ambient temperature swings, high humidity, condensation and ice. The pressure port is machined from a solid piece of stainless steel. No o-rings, organic materials, or welds are exposed to the pressure media, allowing for a leak-proof, all-metal, sealed pressure system. Our transducers operate with all pressure media compatible with stainless steel, including most hydraulic fluids, fuels and refrigerants.
Measurement Types
The most common measurement types for pressure transducers are absolute pressure, gauge pressure, sealed gauge pressure, differential pressure, and compound pressure.
Absolute: pressure is measured relative to a hard vacuum. Typically the devices contains a small vacuum chamber exposed to one side of the sensor and the pressure to be measured is applied to the opposite side. At sea level, an absolute pressure sensor open to the air will read 1 ATM or 14.7psi.
Gauge: Pressure is measured relative to local atmospheric pressure. One side of the sensor is exposed to atmosphere (small hole in the housing), the other side to the pressure to be measured. A gauge sensor, open to the air, will always read zero ATM or zero psi because the same pressure is applied to both sides of the sensor.The device must have a vent path to let local atmosphere in to the body.
Sealed Gauge: Pressure is measured relative to a standard gauge pressure, with no actual reference to atmospheric pressure. Often the device contains an absolute reference and an offset to represent a standard atmosphere is added electronically. This simulates a gauge part without requiring a vent path, and is commonly used for higher pressures where atmospheric variations are of little significance.
Differential: The device has two pressure ports and measures the difference between them. This can be used to measure a small differential pressure at a high line pressure like in filter monitoring. The addition of a second port and consideration of line pressure leads to a large number of scenarios that must be considered when specifying the device.
Compound: Measures both negative and positive gauge pressure. A compound pressure transducer provides a linear output signal from full vacuum through zero pressure up to the full-scale pressure.
Output Signals
Generally speaking, a pressure sensor will have an electrical output that varies linearly with applied pressure. Common output types are:
mV: Typically, a mV signal is derived directly from the sensor bridge with only simple correction electronics. Output will be proportional to the supply voltage (ratiometric). The supply can be constant current or constant voltage. Accuracy is somewhat limited by the simple passive compensations circuits that are typically used.
0.5 to 4.5V Ratiometric: This is common for automotive applications. The device operates from a nominal 5V supply and the output varies proportional to the supply voltage within a specified range. Some diagnostic codes can be provided by controlling the out-of-range output.
Amplified 1-5V: A variety of amplified signals can be provided, most commonly 1-5V. These devices normally contain a regulator so output does not vary with supply voltage.
4-20mA: A common industrial standard requiring only two wires, and having the advantage that the signal is not degraded by a very long wiring run. The device draws 4mA at low pressure and 20mA at full scale pressure. This can be monitored by measuring the voltage across a series resistor.
Digital: There are a wide variety of digital outputs that can be provided, including CANBUS, I2C and SPI.
Comparison chart for HazLoc pressure transducers by protection class, temperature, stability, accuracy, and pressure range.
Transducer Materials
TE Connectivity manufactures pressure transducers from various materials including 17-4 PH stainless steel, 316L, Alloy 718, Alloy C276, and Titanium.
General guidelines on compatibility for pressure transducer materials:
- 17-4 PH Stainless Steel: Hydraulic fluid, air (nitrogen, oxygen, etc), natural gas, freon, paint, steam, plastic molding, diesel fuel, CO2
- 316 L Stainless Steel: Hydrogen, chlorinated water, ammonia refrigerants, petroleum products (crude or processed)
- Alloy 718 / Hastelloy C276: High H2S content gas, saltwater, seawater, high temperature liquids and gases
- Titanium: Medical devices that come in contact with bodily fluids
Common Thread Types
Threaded connections are available in male and female configurations and can be designed with a tapered seal, O-ring, or metal to metal seals. Higher pressure ranges require the connection to be rated for the pressure.
Standard Connections Available
Refer to datasheets for options by model
- 1/4-19 BSPP
- G3/8 JIS B2351
- 7/16-20 UNF male SAE J1926-2 straight thread, o-ring BUNA-N 90SH-904 (O-RING not provided by TE)
- 1/4-18 NPT
- 1/8-27 NPT
- G1/4 JIS B2351
- 1/4-19 BSPT
- 1/4-19 BSPP female (without snubber)
- 7/16-20 UNF female SAE J513 straight thread with integral valve depressor
- 7/16-20 UNF female SAE J513 straight thread
- M10 x 1.0mm ISO 6149-2
- M12 x 1.5mm ISO 6149-2
- G1/4 DIN 3852 form E, gasket DIN 3869-14 NBR (gasket not provided by TE)
- M20 x 1.5mm ISO 6149-2
- M14 x 1.5mm ISO 6149-2
