Response time of differential preassurer sensors limits the temporal resolution

[Mh2]

Hello NXP community,

I am currently setting up a test setup for a research project. I would like to use the two sensors MPX5500DP and MPX5100DP for this. In the data sheet I found the specification “Response Time - t_R - 1 ms” for both sensors. I have interpreted the response time as a rise time compared to data transmission. In this context, a response time of 1 ms means a cut-off frequency of 350 Hz. This in turn would mean that you can only expect a new measurement value every 3 ms. This therefore means that the temporal resolution is 3 ms. Have I got this right?

[ErikaC]

Hello,

The response time 1ms indicates the sensor's output rise time from 10% to 90% of its final value in response to a step change in pressure, corresponding to a cut-off frequency of approximately 350 Hz.  However, the temporal resolution depends on the system's design, including any additional filtering or sampling processes. In theory, the sensor could provide updates every 1 ms, but in practical systems with signal conditioning, the effective temporal resolution might indeed be closer to your estimate of 3 ms.

Hope this helps.

[Mh2]

Thank you @ErikaC for your answer. I am connecting the sensor without any signal conditioning. For my test bench I measure V_out from the sensor directly with an oscilloscope with 80 MSPS. I use this as a DAQ system, as I am only interested in a relatively short time span, which in turn I need in a relatively high temporal resolution. For this, 1 ms is actually much too slow. Unfortunately, I have not found any differential pressure sensors with a higher time resolution.

How I can understand the response time is still not entirely clear to me. The time of 1 ms is always required, regardless of how high the change in differential pressure at the sensor input is? So whether the output voltage rises from 200mV to 209mV or to 300mV is irrelevant, the response time is always 1 ms?

That would mean that I always have a delay of 1 ms in my output signal in respect to the change in the input. And also that the sensor can only start to convert the differential pressure from the input into the output voltage again after 1 ms, i.e. a time resolution of 1 ms.

Can this be assumed?