Arduino library for the DCT532, an I2C industrial pressure and temperature sensor.

Experimental

This library is to use the I2C DCT532 industrial pressure and temperature sensor. The library does not support the RS485 / MODbus version.

The DCT532 is a range of industrial pressure sensors made by BD SENSORS GmbH, www.bdsensors.de. The pressure ranges vary from 0..100 mbar up to 0..60 bar. These sensors have an accuracy (IEC 61298-2) ≤ ± 0.25 % FSO (Full Scale Output).

This library only support the I2C interface, there exists also an RS485 version of the sensor which has more functionality (TODO verify).

The library is not tested with hardware yet.

TODO: extend info here.

For details read the datasheet (www.bdsensors.de).

Feedback as always is welcome.

Pressure range from 100 mbar .. 60 bar.

Note: absolute pressure possible from 0.4 bar

Note: type x102 = -1..0 bar, type 9999 = custom.

TODO add peak to table.

• https://github.com/RobTillaart/pressure pressure conversions
• https://github.com/RobTillaart/Temperature temperature conversions
• https://github.com/RobTillaart/MS5611 temperature pressure sensor
• https://github.com/RobTillaart/MS5837 temperature pressure sensor
• https://github.com/RobTillaart/MSP300 industrial pressure transducer
• https://swharden.com/blog/2017-04-29-precision-pressure-meter-project/

The device has a fixed I2C address 0x28 (40 dec).

Sometimes you need to control more devices than possible with the default address range the device provides. This is possible with an I2C multiplexer e.g. TCA9548 which creates up to eight channels (think of it as I2C subnets) which can use the complete address range of the device.

Drawback of using a multiplexer is that it takes more administration in your code e.g. which device is on which channel. This will slow down the access, which must be taken into account when deciding which devices are on which channel. Also note that switching between channels will slow down other devices too if they are behind the multiplexer.

• https://github.com/RobTillaart/TCA9548

Only test readSensor() as that is the main function.

TODO: run performance sketch on hardware.

#include "DCT532.h"

• DCT532(uint8_t address, TwoWire *wire = &Wire) optional select I2C bus.
• bool begin(float maxPressure, float minPressure = 0) sets the range of the sensor, the maximum pressure needs to be set explicit. Furthermore it resets the internal variables. Returns true if device address is visible on the I2C bus.
• bool isConnected() returns true if device address is visible on the I2C bus.
• uint8_t getAddress() Returns the address set in the constructor (convenience).

• int readSensor() does the actual reading of the sensor, returns DCT532_OK (0) or an error code.
• float getPressure() returns the last pressure in BAR.
• float getTemperature() returns the last temperature in degrees Celsius.
• uint32_t lastRead() timestamp in millis of last read. Can be used for schedule timed measurements.

• int getLastError() returns last error of the low level communication.

TODO: insert table

DCT532_OK = 0

• improve documentation
• get hardware to test proper working of the library

• improve error handling
• other registers accesible over I2C?
• do performance test
• remove P and T as private variables when library works.
• write examples

• create unit tests if possible
• derived classes for specific P sensors?
• do we need minimum pressure?
• do we need offsets to calibrate?
• float getPmin(), float getPmax() for debugging?
• setType() getType() function ?

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