Digilent Pmod DPG1是一個壓差計模組。模組內建 NXP MP3V5010DP 壓阻感測器和Texas Instrument 12位元類比數位轉換器 ADCS7476 ，可以檢測出兩個介面之間的壓力所發生的變化，並且將數位資訊發送到系統板：
- 差壓感測器
- 12位元ADC
- 0到10 kPa差壓範圍
- 溫度補償和校準功能
- 適用於各種設計的小型 PCB (2.54公分×2.0公分）
- SPI 介面的 6 pin Pmod 連接器
Pinout Table Diagram
| Pin | Signal | Description |
|---|---|---|
| 1 | SS | Chip Select |
| 2 | NC | Not Connected |
| 3 | MISO | Master-In-Slave-Out |
| 4 | SCK | Serial Clock |
| 5 | GND | Power Supply Ground |
| 6 | VCC | Power Supply (3.3V) |
The Pmod DPG1 is capable of converting up to 1 MSa per second of 12-bit data, but the transducer response time to a step change of 1 kPa is 1 ms. Smaller changes in pressure will take less time for the transducer to change its output voltage.
Specifications
| Parameter | Min | Typical1 | Max | Units |
|---|---|---|---|---|
| Recommended Operating Voltage | 3.125 | 3.3 | 3.5 | V |
| Maximum Supply Voltage | - | - | 5.5 | V |
| Maximum Pressure2 | - | - | 75 | kPa |
| Minimum Pressure Offset3 | 0.1 | 0.24 | 0.38 | V |
| Sensor Accuracy | -0.54 | 0 | 0.54 | kPa |
| Parameter | Value | Units | ||
| Communication Protocol | SPI Mode 04 | |||
| Power Supply Current draw5 | 10 | mA | ||
| Sensor Response Time | 1 | mS | ||
| Sensor Bandwidth | 500 | Hz | ||
Note2 - Where the pressure at P1 (top nozzle) is greater than the pressure at P2 (bottom nozzle)
Note3 - Output voltage corresponding to a pressure differential of 0 kPa
Note4 - CPOL = 0, CHPA = 0
Note5 - Normal operation with VCC at 3.3V
Interfacing with the Pmod
The Pmod DPG1 communicates with the host board via the SPI protocol with SPI Mode 0 (CPOL = 0, CHPA = 0). The 12 bits of digital data are sent to the system board in 16 clock cycles with the most significant bit first. For the embedded ADC7476, each bit is shifted out on each falling edge of the serial clock line after the chip select line is brought low with the first four bits as leading zeroes and the remaining bits representing the 12 bits of data. The datasheet for the ADC7476 recommends that for faster microcontrollers or DSPs that the serial clock line is first brought to a high state before being brought low after the fall of the chip select line to ensure that the first bit is valid. As a differential pressure module, it should be noted that the Pmod can only accept a certain range of pressure differences without damaging the internal piezoresistive silicon. When the Pmod is laid on a flat surface such that transducer is above the PCB, the top most nozzle is P1 (the receiving nozzle to detect fluctuating pressure) and the bottom most nozzle is P2 (the pressure reference nozzle for P1). The pressure at P1 is recommended to be between 0 and 10 kPa above the pressure present at P2. Pressures outside of this range may cause permanent damage to the device. To convert the serial data stream back into a corresponding pressure, users may use the following equation:
The Pmod DPG1 communicates with the host board via the SPI protocol with SPI Mode 0 (CPOL = 0, CHPA = 0). The 12 bits of digital data are sent to the system board in 16 clock cycles with the most significant bit first. For the embedded ADC7476, each bit is shifted out on each falling edge of the serial clock line after the chip select line is brought low with the first four bits as leading zeroes and the remaining bits representing the 12 bits of data. The datasheet for the ADC7476 recommends that for faster microcontrollers or DSPs that the serial clock line is first brought to a high state before being brought low after the fall of the chip select line to ensure that the first bit is valid. As a differential pressure module, it should be noted that the Pmod can only accept a certain range of pressure differences without damaging the internal piezoresistive silicon. When the Pmod is laid on a flat surface such that transducer is above the PCB, the top most nozzle is P1 (the receiving nozzle to detect fluctuating pressure) and the bottom most nozzle is P2 (the pressure reference nozzle for P1). The pressure at P1 is recommended to be between 0 and 10 kPa above the pressure present at P2. Pressures outside of this range may cause permanent damage to the device. To convert the serial data stream back into a corresponding pressure, users may use the following equation:
What can I safely measure with the Pmod DPG1
The recommended pressure differential range for the embedded MP3V5010 on the Pmo dDPG1 is between 0 kPa and 10 kPa, so it is ideally suited for applications such as measuring small pressure changes inside a venturi meter, as a pressure plate to detect when something touches it, or to determine the air pressure exerted by the normal human lung (presuming you are not a trumpet player or in another field where you need above average lung pressure). Notably, the Pmod DPG1 is not able to measure the air pressure inside of a car or bike tire.
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通訊協議/介面：SPI |
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DIGILENT Pmod Interface Specification類型/版本：TYPE 2 / 1.2.0 |
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產品文件：產品規格│原理圖 │ 資源中心 |
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產品編號：410-333 |
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