Decagon ES-2 module

Introduction

If you still have one of these sensors, it is implemented as a sub-classes of the SDI12Sensors class. It requires a 3.5-12V power supply, which can be turned off between measurements. While contrary to the manual, they will run with power as low as 3.3V. On the version with a stereo cable, the power is connected to the tip, data to the ring, and ground to the sleeve. On the bare-wire version, the power is connected to the white cable, data to red, and ground to the unshielded cable.

Sensor Datasheet

• Manual
• Integrator's Guide

Build flags

Sensor Constructor

Example Code

The Decagon ES-2 is used in the menu a la carte example.

#include <sensors/DecagonES2.h>

// NOTE: Use -1 for any pins that don't apply or aren't being used.
const char*   ES2SDI12address   = "3";  // The SDI-12 Address of the ES2
const int8_t  ES2Power          = sensorPowerPin;  // Power pin
const int8_t  ES2Data           = 7;               // The SDI-12 data pin
const uint8_t ES2NumberReadings = 5;

// Create a Decagon ES2 sensor object
DecagonES2 es2(*ES2SDI12address, ES2Power, ES2Data, ES2NumberReadings);

// Create specific conductance and temperature variable pointers for the ES2
Variable* es2Cond = new DecagonES2_Cond(&es2,
                                        "12345678-abcd-1234-ef00-1234567890ab");
Variable* es2Temp = new DecagonES2_Temp(&es2,
                                        "12345678-abcd-1234-ef00-1234567890ab");

Classes

class DecagonES2

The Sensor sub-class for the Decagon ES-2 sensor.

class DecagonES2_Cond

The Variable sub-class used for the conductivity output from a Decagon ES-2 electrical conductivity sensor.

class DecagonES2_Temp

The Variable sub-class used for the temperature output from a Decagon ES-2 electrical conductivity sensor.

Defines

#define ES2_NUM_VARIABLES = 2

Sensor::_numReturnedValues; the ES2 can report 2 values.

#define ES2_INC_CALC_VARIABLES = 0

Sensor::_incCalcValues; we don't calculate any additional values.

Sensor Timing

The sensor timing for a Decagon ES-2

#define ES2_WARM_UP_TIME_MS = 250

Sensor::_warmUpTime_ms; maximum warm-up time in SDI-12 mode: 250ms.

#define ES2_STABILIZATION_TIME_MS = 0

Sensor::_stabilizationTime_ms; the ES2 is stable as soon as it warms up (0ms stabilization).

#define ES2_MEASUREMENT_TIME_MS = 250

Sensor::_measurementTime_ms; maximum measurement duration: 250ms.

#define ES2_EXTRA_WAKE_TIME_MS = 0

Extra wake time required for an SDI-12 sensor between the "break" and the time the command is sent. The ES-2 requires no extra time.

Conductivity

The conductivity variable from a Decagon ES-2

• Range is 0 – 120 mS/cm (bulk)
• Accuracy is ±0.01mS/cm or ±10% (whichever is greater)

#define ES2_COND_RESOLUTION = 1

Decimals places in string representation; conductivity should have 1.

0 are reported, adding extra digit to resolution to allow the proper number of significant figures for averaging - resolution is 0.001 mS/cm = 1 µS/cm

#define ES2_COND_VAR_NUM = 0

Sensor variable number; conductivity is stored in sensorValues[0].

#define ES2_COND_VAR_NAME = "specificConductance"

Variable name in ODM2 controlled vocabulary; "specificConductance".

#define ES2_COND_UNIT_NAME = "microsiemenPerCentimeter"

Variable unit name in ODM2 controlled vocabulary; "microsiemenPerCentimeter" (µS/cm)

#define ES2_COND_DEFAULT_CODE = "ES2Cond"

Default variable short code; "ES2Cond".

Temperature

The temperature variable from a Decagon ES-2

• Range is -40°C to +50°C
• Accuracy is ±1°C

#define ES2_TEMP_RESOLUTION = 2

Decimals places in string representation; temperature should have 2.

1 is reported, adding extra digit to resolution to allow the proper number of significant figures for averaging - resolution is 0.1°C

#define ES2_TEMP_VAR_NUM = 1

Sensor variable number; temperature is stored in sensorValues[1].

#define ES2_TEMP_VAR_NAME = "temperature"

Variable name in ODM2 controlled vocabulary; "temperature".

#define ES2_TEMP_UNIT_NAME = "degreeCelsius"

Variable unit name in ODM2 controlled vocabulary; "degreeCelsius" (°C)

#define ES2_TEMP_DEFAULT_CODE = "ES2Temp"

Default variable short code; "ES2Temp".