Truebner FAQ

Truebner sensors have outstanding quality and are generally very fail-safe. If a sensor does fail, it doesn't 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 doing garden work, the cable was damaged or there was corrosion on the contacts.
    Tip: Please carry out cable repairs or cable extensions as follows: LINK
    (Note: Please remember to put on the shrink tubing before soldering)
  • Wrong interface variant:
    Analogue sensors cannot be read digitally and digital sensors cannot be read out analogue
  • wrong software:
    The readout software processes the measurement data incorrectly
  • incorrect parameters during data transfer:
    Especially with RS485 sensors, the sensors must receive a device address and the parameters must be specified correctly
  • wrong connection:
    Wiring not according to specifications
  • incorrect voltage:
    Analog sensors require at least 2V more than the signal voltage, so at 0-10V at least 12V. For RS485 sensors at least 5V. Only DC, no AC!

1. Voltage and cable problems

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

a) Cable ends of all types

Corrosion: Check the cable ends for damage or corrosion. If the ends are in water, the copper begins to corrode and this runs through the pipes (copper turns black). This in turn leads to excessively increased resistance and at some point there is no longer any contact. Gradually cut off the cable ends until a perfect copper wire is visible again. Lay the cable in a hose or pipe. Use waterproof connectors.

b) Interface variant

Checking the correct interface variant:  Hold the green measuring surface up to the light. You should then see the marking SMT100 XYZ, where XYZ corresponds to the interface variant. Modbus and ASCII/Text are both RS485

c) Analogue sensors (SMT50 and all analogue versions of SMT100, Aquaflex and HT100)

  1. Check the cabling and the power supply, there must be one DC voltage source be used.
  2. Measure with one measuring device the voltage at brown (+V) and white (GND), the voltage must be the Supply voltage are equivalent to.
  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 2.

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

  1. Check the cabling and the power supply, there must be one DC voltage source be used.
  2. Use a measuring device to measure the voltage at brown (+V) and white (GND), the voltage must be the Supply voltage are equivalent to.
  3. RS-485: If you have a USB RS-485 adapter, load that Truebner Modbus Software Download it and try to read out the data. If this works correctly, the sensor is OK.
  4. Otherwise: write them down Measurement Values via your existing software.
  5. The measured values ​​must be converted. Read on the Truebner support page the documents, like that calculation must be carried out. Aquaflex and HT100 are calculated like the SMT100
  6. If the measured values ​​do not match or the sensor no longer responds, then continue with 2.

2. Preparation for Truebner support

Before sending in the sensor we need some first Control data.

  1. Do you have the above Notes noticed?
  2. Create Photos of their installation and the device connection
  3. Use Distributor? If so, which ones and how connected?
  4. Make a note adapters/Controllers (the devices to which the sensors are connected) the name and type.
  5. Write these down Voltage values.
  6. Did it already work or is this a new one? configuration?
  7. For incorrect values: Please explain which value is incorrect and what you would expect.

Send this to support@OpenSprinklerShop.de