# Bar30 Pressure Sensor resolution

**URL:** <https://discuss.bluerobotics.com/t/bar30-pressure-sensor-resolution/1458>\
**Category:** Sensors\
**Created:** [September 5, 2017, 7:25pm UTC](https://discuss.bluerobotics.com/t/bar30-pressure-sensor-resolution/1458 "2017-09-05T19:25:22Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lamhung81](https://avatars.discourse-cdn.com/v4/letter/l/c4cdca/32.png) [@lamhung81](https://discuss.bluerobotics.com/u/lamhung81)\
**Post date:** [September 5, 2017, 7:25pm UTC](https://discuss.bluerobotics.com/t/bar30-pressure-sensor-resolution/1458/1 "2017-09-05T19:25:22Z")

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Hi all,

I am working on a project that we would like to modify PX4 open-source code for adapting to AUV control.

I wrote a driver for MS5837-BA30 pressure sensor. This is basically based on the driver (included in PX4) of on-board MS5611 sensor of Pixhawk.

The new driver works. However, values of Pressure [in mBar] is so noisy. For case when the sensor is on the air, with reading frequency of about 18Hz, P max = 1032.5, P min =1030.2. Then one calculates delta P = 2.3 mBar, if underwater should be 2.3 cm of depth change.

I read on the Bluerobotics website that the resoluion is 0.2 mBar.

If there anyone have the same problem when reading data from the pressure sensor, in PX4 opensoure or Ardusub?

Here in the below are value read from screen /dev/ttyUSB0 57600

INFO [raw\_pressure] Pressure: 1030.7001 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.1000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1032.2001 Temperature: 27.8100  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.1000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.3000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1033.0000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1030.2001 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1030.3000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1032.3000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1032.1000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.1000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1032.3000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.3000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.1000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.3000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1030.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.3000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1032.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1032.3000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1030.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1030.9000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1031.5000 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1031.7001 Temperature: 27.8300  
INFO [raw\_pressure] Pressure: 1030.9000 Temperature: 27.8200  
INFO [raw\_pressure] Pressure: 1032.3000 Temperature: 27.8200

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<div class="post-metadata">

**Author:** ![jwalser](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/jwalser/32/2234_2.png) [@jwalser](https://discuss.bluerobotics.com/u/jwalser)\
**Post date:** [September 15, 2017, 3:06pm UTC](https://discuss.bluerobotics.com/t/bar30-pressure-sensor-resolution/1458/2 "2017-09-15T15:06:13Z")

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You should filter the data. Accuracy, precision, and resolution are [different](http://kb.mccdaq.com/KnowledgebaseArticle50043.aspx). The sensor is operating within specification.