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Sensoray Model 118 Smart A/D™ Instruction Manual 22 Commands: Sensor Acquisition

6.3 Sensor Acquisition

6.3.1 GetSensorData

Returns the most recently acquired sensor data from a

channel. The returned 16-bit integer value is scaled as a

function of the declared channel sensor type.

Regardless of sensor type, the returned value is always

represented in 16-bit two’s complement integer form.

The returned value must be multiplied by an appropriate

scalar to convert it to floating point engineering units.

Refer to Table9 on page36 for a list of sensor scalars.

Driver

// Read sensor data from specified channel in appropriate engineering units.

// Scalar converts integer sensor data to engineering units.

DOUBLE GetSensorData( USHORT BasePort, UCHAR Channel, DOUBLE Scalar )

{

SendByte( BasePort, Channel ); // request sensor data

return Scalar * (DOUBLE) ReadWord( BasePort ); // return scaled data

}

Example

// Read voltage at Channel 6, which is configured for 5V, 200uV/bit range.

DOUBLE Chan6volts = GetSensorData( MyBasePort, 6, SCALAR_VOLTS_5 );

Example

// Read temperature (in degrees C) at channel 4, which is configured for

// a type K thermocouple.

DOUBLE Chan4temp = GetSensorData( MyBasePort, 4, SCALAR_TC_K );

Command: (Chan)

Response: (DataMSB),(DataLSB)

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Sensoray 118 Manuel d'utilisateur Page 24