Truebner FAQ

Truebner Sensors are of outstanding quality and are generally very reliable. If a sensor does fail, it does not necessarily have to be a defective sensor.

In 99% of all cases so far, the reasons were the following:

  • Damaged cable:
    When installing the sensor or during gardening work, the cable was damaged or there was corrosion on the contacts.
  • wrong software:
    The reading software processes the measurement data incorrectly
  • incorrect parameters during data transfer:
    Especially with RS485 sensors, the parameters must be specified correctly
  • wrong connection:
    Wiring not according to specifications
  • wrong voltage:
    Analog sensors require at least 2V more than the signal voltage, so at least 0V for 10-12V. At least 485V for RS5 sensors. Only DC, no AC!

1. Voltage and cable problems

If a sensor does not work as expected, please proceed as follows:

a) Cable ends all types

Corrosion: Check the cable ends for damage or corrosion. If the ends have been in water, the copper begins to corrode and this will spread through the cables (copper turns black). This in turn leads to excessive resistance and eventually no contact will be made. Cut off the cable ends one by one until a perfect copper wire is visible again. Lay the cable in a hose or pipe. Use waterproof connectors.

b) Analog sensors (SMT50 and all analog versions of SMT100, Aquaflex and HT100)

  1. Check the wiring and the power supply, there must be a DC voltage source should be used.
  2. Measure with one Measuring device the voltage to brown (+V) and white (GND), the voltage must be Supply voltage correspond.
  3. Then the voltages green - white (temperature) and yellow - white (soil moisture). A voltage below the supply voltage must be measurable here. You may have to put the sensor in a glass of water so that the soil moisture can be measured.
  4. If no voltage can be measured, the cable is probably damaged.
  5. In all other cases, go to step 2.

c) Digital sensors (SMT100 RS485 Modbus/TBus/Ascii, LV, TTL, SDI)

  1. Check the wiring and the power supply, there must be a DC voltage source should be used.
  2. Use a measuring device to measure the voltage at brown (+V) and white (GND), the voltage must be Supply voltage correspond.
  3. RS-485: If you have a USB-RS-485 adapter, download the Truebner Modbus software and try to read the data. If this works properly, the sensor is OK.
  4. Otherwise: Write down the measurements about their existing software.
  5. The measured values ​​must be converted. Read on the Truebner Support page the documents, such as the calculation Aquaflex and HT100 are calculated like the SMT100
  6. If the measured values ​​do not match or the sensor no longer responds, go to step 2.

2. Preparation for the Truebner Support

Before you send in the sensor, we first need some control data.

  1. Have you answered the above Notes noticed?
  2. Create Photos from their installation and device connection
  3. Use Distributor? If so, which ones and how are they connected?
  4. Make a note of adapters/Controllers (the devices to which the sensors are connected) the name and type.
  5. Note the voltage values.
  6. Did it work before or is this a new Configuration?
  7. If the values ​​are incorrect: Please explain which value is incorrect and what you would expect.

Please send this to support@opensprinklershop.de