Virtual sensors can be created that calculate their values from other sensors.
In this example (with hourly readings), daily maximum, minimum and average values are being calculated from 06:00 to 06:00 - the period could have been weekly or monthly.
In addition to separate calculated sensors, each sensor can 'internally' calculate and graph varying upper, varying lower, smooth, rate, and integration using .
The advantage of using the extra, internal, sensors is that they are easy to use; but they cannot be individually customised. Colours and lines styles can be set on .
If you need to customise a calculated sensor you will need to create a separate sensor with . Calculated sensors are customised in the same way as a normal sensor ( and )
The following functions are available...
| ID | Formula | Notes | Inputs required |
|---|---|---|---|
| 3 | Smooth | Smooths the values | Sensor,Factor |
| 3.1 | Method1 | Moving average over the previous number of day(s) | Sensor,day(s) |
| 3.2 | Method2 | Digital filter, with factor and Jump | Sensor,Factor,Jump |
| 3.3 | Method3 | Polynomial (not implemented) | Sensor |
| 3.4 | Method4 | FFT (not implemented) | Sensor |
| Rate | Rate of change (per day) | Sensor | |
| 1. | Method1 | Difference between 2 consecutive readings | Sensor |
| 1.21 | Method2* | Difference between reading a numbers of days)(s) apart (with Jump from Smooth) | Sensor, Days(s), Jump |
| 1.3 | Method3* | Difffrence between readings at 6:00 a.m. on consecutive days | Time (hh:mm) |
| 2 | Integrate | Accumulates total of value | Sensor |
| 15 | RTOTAL * | Total of values in period | Sensor,Period** |
| 14 | RAVERAGE * | Average value in period | Sensor, Period** |
| 16 | RCOUNT * | Count of values in period | Sensor, Period** |
| 10 | RMAXIMUM * | Maximum value in period | Sensor, Period** |
| 12 | RMINIMUM * | Minimum value in period | Sensor, Period** |
| 8 | GDD | Growing degree days | MaxTemp, MinTemp, base temperature |
| 9 | PENMAN | ET0 FAO12345 - replaced by below | MaxTep, MinTemp, RH, WR |
| 23 | AVERAGE | Average of 2 other sensors at same date | Sensor1, Sensor2 |
| 24 | Difference | Difference between 2 other sensors | Sensor1, Sensor2 |
| 25 | Sum | Total of 2 other sensors | Sensor1, Sensor2 |
| 26 | Max | Maximum of 2 other sensors | Sensor1, Sensor2 |
| 27 | Min | Minimum of 2 other sensors | Sensor1, Sensor2 |
| 4 | LOOKUP | Looks up a value in another file | Sensor
File name (comma or tab delimited) Column in file of known values Column in file with result Style - interpolated |
| 5 | DWULOOKUP | Calculated value from DWU file on DayOfYear() file needs to be in DWU format |
DWU file name Column in file with dwu value (default = Col2) Style = interpolate | use previous | use next value in file |
| 6 | LOOKUPOTHER | Interpolates value of sensor in another logger (with different dates)
Note: v2.1.036 all functions allow the target sensor to be in any logger. |
Sensor |
| 7 | ROOTZONE | Total amount of water in root zone | All sensors in same logger with a 'depth' >0 |
| 20 | DELTAT | Calculates DeltaT from air temperature and RH - see Bureau of Meteorology | Air temperature (degC) RH(%) |
| 22 | RDI | Calculate value of varying upper or lower limit from file. Limit can be either...
File must be in DWU format |
Sensor RDI file name Column in file with RDI value (default = Col2) |
| 30 | CWSI(Zen) | Calculation of Zen Crop Water Stress Index
Value = (AirTemperature - CanopyTemperature) * RH Geoffrey Phelps |
Sensor1: Air Temperature
Sensor2: Canopy Temperature Sensor3: RH |
| 31 | CWSI | Calculation of Crop Water Stress Index
Value = f(AirTemperature, CanopyTemperature, VPD, RH ??) |
Sensor1: Air Temperature
Sensor2: Canopy Temperature Sensor3: VPD Factor1: Upper Limit Factor2: Lower Slope Factor3: Lower(Offset) |
| 32 | ET0 Hourly (FAO 56) | ET0 from Temperature, RH, SR, Wind Speed |
Sensor1: Air Temperature
Sensor2: Solar Radiation Sensor3: RH Sensor4: Wind Speed Factor1: Station (e.g. Goanna) Factor2: Crop Factor (e.g. 0.9) |
| 33 | ET0 Daily (FAO 56) | ET0 from daily Temperature, RH, Wind
using FAO 56 (CSIRO, Griffith) |
Sensor1: Temperature Max Sensor2: Temperature Min Sensor3: RH Max Sensor4: RH Min Sensor5: Solar Rad Sensor6: Wind speed Factor1: StationName (e.g. Goanna) Factor2: Crop Factor Factor3: Adjust |
| 34 | SoilMoisture from ET0 | Calculate the soil water balance using ET
Sensor2 is measured soil moisture Starting value from Sensor2 Increase if gain detected in Sensor2 |
Sensor1: ET
Sensor2: Measured Sensor3: Rain Sensor4: Irrigations |
* Needs continuous logged data at equal time intervals.
** Period can be in days (e.g. '1d'), weeks (e.g. '1w') or months (e.g. '1m')
After v 2.1.036, the sensors can be in any logger. This would allow, for example, a sensor to calculate the difference between temperature recorded on two separate loggers.