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Compost Soil Sensor Program

Acquire data from temperature/RH probe and thermocouples using a Campbell Scientific CR1000 and send serial data messages to DAQFactory.

Wiring

The CR1000 is powered from a 12V power adapter. Be sure to turn the logger off before adding or removing sensors. Its program will run automatically whenever power is applied.

Thermocouples

Four Type K thermocouples are connected to differential inputs 1-4:

Note standard thermocouple wiring convention is red = negative.

Description Color CR1000
Thermocouple #1 signal (+) yellow DF 1 H (SE1)
Thermocouple #1 ground (-) red DF 1 L (SE2)
Thermocouple #2 signal (+) yellow DF 2 H (SE3)
Thermocouple #2 ground (-) red DF 2 L (SE4)
Thermocouple #3 signal (+) yellow DF 3 H (SE5)
Thermocouple #3 ground (-) red DF 3 L (SE6)
Thermocouple #4 signal (+) yellow DF 4 H (SE7)
Thermocouple #4 ground (-) red DF 4 L (SE8)

Temperature/RH probe

The temperature/relative humidity probe (CS215; Campbell Scientific) is connected to port C1 and data is

Description Color CR1000
Power input red 12V
Power ground black G
Power ground white G
SDI-12 data green C1
shield clear G

Soil moisture/temperature probes

These sensors were removed

Six soil moisture & temperature probes (5TM; Decagon Devices) are connected to the first SDI-12 port using three sets of screw terminals.

The SDI-12 addresses of the sensors are 7, 8, 9, A, B, C. The address is used in variable names and serial data messages to uniquely identify the sensor.

Note legacy color scheme for 5TM sensors is white = power. Connecting the red wire to a power source will destroy these sensors.

DAQFactory Computer

Use a serial cable and usb serial adapter, if needed, to connect the DAQFactory computer to the RS-232 port of the CR1000. The serial port configuration is:

  • Baud rate: 115200
  • Data bits: 8
  • Parity: none
  • Stop bits: 1

Copy the custom protocol file CR1000.ddp into the DAQFactory installation folder and restart DAQFactory. Then create a new serial device using the above settings and specify the custom protocol "CR1000" for that device.

One serial data record is sent by the datalogger after each scan.

  • Each record:
    • is prefixed with TC
    • and is delimited with a carriage return and line feed (\r\n)
    • contains thermocouple (TC) data for differential input channels 1, 2, 3, and 4, respectively
  • However:
    • the DAQFactory protocol file skips over thermocouple #3 (not connected)

Data Products

The logger queries sensors for new values and records data every 5 seconds. The record is stored to internal memory in a ring-fill mode (e.g. newest overwrites oldest when full).

  • Base name: compost_soil
  • Record interval: 5 seconds
  • Timestamp anchor: prior interval, e.g. 00:02:00 = avg(00:01:00-00:01:59)

Soil probe temperature is obtained from a thermistor in the overmold. Volumetric water content is calculated from the measured apparent dielectric permittivity value using the Topp equation[ref], though users may wish to explore using a different media-specific calibration curve.

Field name Units Description
TC1_tmpr_Avg degC temperature from DF1 thermocouple
TC2_tmpr_Avg degC temperature from DF2 thermocouple
TC3_tmpr_Avg degC temperature from DF3 thermocouple
TC4_tmpr_Avg degC temperature from DF4 thermocouple
CS215_T_Avg degC temperature from CS215 probe
CS215_RH_Avg percent relative humidity from CS215 probe

Licensing

  • Original software contributions are licensed under the MIT License
  • Screenshots and documentation are licensed under CC-BY-SA-4.0 (Creative Commons Attribution-ShareAlike 4.0 International)

References