Extend operating range of LPS28DFW using autozero functionality

[wstuchbury]

I am working on a project using the LPS28DFW pressure sensor to monitor depth in water (~1000mBar / 10m), the sensor has a max operating range of up to 4096 mBar limited by its 24 bit 2s compliment output. As far as I can tell the negative half of the output range is never used unless autozero functionality is used, so I was hoping to use this to offset the pressure by a large value (ideally -4096) to better utilise the output range of the 2s compliment 24 bit output.

I have ran into 2 issues with this; first the REF_P (L and H) registers are read only, so I can't set a fixed offset, second the differential output is only put into the normal output registers and not into the FIFO.

Is there any way around this? I see there is also a one time programable offset although ideally we would have control over when to offset for the extra range so the autozero function would be better.

[Federica Bossi · Accepted solution]

Hi @wstuchbury ,

The purpose of the offset is to create an alignment between different devices in standard condition. The dynamic of the register is developed for the maximum pressure of the sensor. For this reason, the offset doesn't change the maximum pressure of the device (around 4060hPa) that is the maximum pressure can be reached from our sensor. We are developing a new device pin to pin compatible with LPS28DFW with extended pressure range.

[wstuchbury]

Thank you for the reply, do you have a link for any further info on this new device?

[Federica Bossi]

Hi @wstuchbury ,

Have you already looked at the documentation section on our website?

[wstuchbury]

I have looked through the documentation for the LPS28DFW but can't see any mention of this new device with extended pressure range