Product Description : The MPX5500 series piezoresistive transducer is a state–of–the–art monolithic silicon pressure sensor designed for a wide range of applications, but particularly those employing a microcontroller or microprocessor with A/D inputs. This patented, single element transducer combines advanced micromachining techniques, thin–film metallization, and bipolar processing to provide an accurate, high level analog output signal that is proportional to the applied pressure. Specifications : Item Type : Pressure Sensor Model : MPX5500DP Accuracy (% Error) (Max) : 2.5(%) Pressure range : 0 to 500 kPa Supply voltage ：5V Level of Integration ：integrated Features 2.5% Maximum Error over 0° to 85°C Ideally suited for Microprocessor or Microcontroller–Based Systems Durable Epoxy Unibody Element Available in Differential and Gauge Configurations Package Includes : 1X MPX5500DP IC Pressure Sensor
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I found the output to be very unstable, though within specifications
I purchased the MPX 5500 knowing that at 500 kPa it vastly exceeded the range I needed, which was about 100 kPa, for use with a research vacuum system. Nevertheless, I thought the extra range might make it more versatile for other applications and I expected to be able to calibrate the unit to account for the reduced accuracy.I first tested the unit to determine the power supply sensitivity and determined that the output varied by 0.4 V/V as the supply voltage was increased from 4.8 V to 5.2 V, which would not be a factor for my system applications. I connected decoupling and filtering exactly as described in the datasheet.I anticipated the unit would be temperature sensitive, so I attached a low-mass thermistor to pin 4 so it would be in good thermal contact with (though electrically isolated from) the sensor element. I placed the assembly into a custom 3D printed enclosure to thermally insulate it and ensure that the temperature of the assembly would not experience thermal transients due to air currents. Finally I connected the two ports together with a short length of tubing to ensure there would be zero differential pressure for the tests.Data were collected at 1 second intervals with 1000 points averaged for each interval, as the supply voltage, thermistor resistance, and sensor output voltage were monitored. The results surprised me a great deal. There was some temperature sensitivity, as expected but it did not seem to be uniform in a way that would allow me to perform hardware or software thermal compensation. This is particularly noticeable in the latter portion of the attached plot, where the indicated pressure stops tracking the temperature change. This concerned me less than the excursions in the indicated pressure, especially in the early part of the experiment. The pressure variations were within the liberal +/- 2.5% specification for the sensor but could not be correlated with temperature or power supply voltage (which was quite stable) and thus could not be compensated in any way.The sensor is probably fine for most applications but for anyone anticipating the ability to provide calibration and compensation to improve its accuracy beyond the stated specifications it may not be possible to do so. I will purchase an MPX 5100 (100 kPa) to reduce the variations in output but I anticipate that it will exhibit similar characteristics and thus may not be able to provide the ability to calibrate and compensate its performance.
TrustPilot
2 个月前
1天前
