### 154N-030A-R Pressure Sensor Overview The **154N-030A-R** is a high-performance, media-isolated, piezoresistive silicon pressure sensor manufactured by **TE Connectivity (Measurement Specialties)**. It is designed for applications where the sensing element must be protected from harsh or corrosive fluids. --- ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Pressure Range** | 0 to 30 psi | | **Pressure Type** | Absolute | | **Sensing Element** | Piezoresistive Silicon | | **Output Type** | Analog Voltage (uncompensated) | | **Supply Current** | 1.5 mA (constant current) | | **Accuracy / Linearity** | ±0.1% FSO (Full Scale Output) | | **Operating Temp** | -40°C to +125°C | | **Material** | 316L Stainless Steel Housing | --- ### Key Components and Construction #### 1. Piezoresistive Die The "heart" of the sensor is a silicon micro-machined chip. When pressure is applied, the chip deforms, changing its electrical resistance. This change is measured via a Wheatstone bridge circuit. #### 2. Oil-Filled Cavity The silicon die is submerged in a small cavity filled with **silicone oil**. This oil acts as a transmission medium, transferring external pressure to the chip while protecting the sensitive electronics from the process media. #### 3. 316L Stainless Steel Diaphragm The sensor features a thin, flexible stainless steel diaphragm. The process fluid (gas or liquid) presses against this diaphragm, which then pushes the silicone oil. Because the diaphragm is 316L stainless steel, it is highly resistant to corrosion. --- ### Pinout Configuration The sensor typically features a ribbon cable or header pins. The standard bridge configuration is as follows: | Pin Number | Function | | :--- | :--- | | **Pin 1** | - Output (Signal -) | | **Pin 2** | - Excitation (Current -) | | **Pin 3** | + Excitation (Current +) | | **Pin 4** | + Output (Signal +) | | **Pin 5/6** | Temperature Compensation Resistors (Internal) | --- ### Use Cases * **Medical Instruments:** Dialysis machines and infusion pumps. * **Process Control:** Pressure monitoring in industrial pipelines. * **Freshwater/Wastewater:** Monitoring levels or flow rates in non-corrosive liquids. * **Automotive:** Manifold pressure or hydraulic fluid monitoring. --- ### Application Note: Signal Conditioning Because the **154N-030A-R** is an uncompensated, non-amplified sensor, it outputs a small millivolt (mV) signal. To use it with a microcontroller (like an Arduino or ESP32), you will typically need: 1. **Instrumentation Amplifier:** To boost the mV signal to a 0-5V or 0-3.3V range. 2. **Precision Current Source:** To provide a stable 1.5mA excitation. 3. **ADC:** A high-resolution Analog-to-Digital Converter for accurate readings.