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Data Transmission FAQs

Your questions answered about telemetry and technical information.

Sentek probes can be fitted with a choice of interfaces that operate in standard industry communication protocols:

  • Modbus RS485
  • Modbus RS232
  • SDI-12

There are a few simple measures you can take to prolong the life of your battery over multiple growing seasons:

  • For solar powered 12v batteries i.e. RT6, Multi and Plus systems: maintain a continuous charge outside of the growing season.
  • For lithium battery packs i.e. Plus All-In-One and Plus Compact systems: ensure the dial-in time (i.e. logger tab/probe configuration utility) is set to 0:00:00 when you configure your probe for the first time. When it is not in use, disconnect the battery from the probe. Depending on sample and upload rates, a lithium battery pack can power your probe for 1 to 2 years.

The Sentek range includes 4G modem telemetry, and our unique Bluetooth data retrieval system. Sentek is also proud to provide an open integration platform for our entire product range. Our probes can connect to a range of third party systems including:

  • data loggers
  • radio telemetry products
  • weather stations
  • GPRS, 3G, CDMA and satellite communication modules
  • irrigation controllers

There have been several instances where Bluetooth probes indicate a low battery or the battery voltage drops so low that they stop sampling or even reset. An investigation shows the plastic in the battery holder is distorting when the battery cap is tightened to a certain point. This then causes the battery to jam which results in thermal expansion over daily temperature cycles, which may then cause missing data and low battery.

Learn how to solve the issue here:

Quick Fix for Bluetooth Low Battery and Missing Data

The easiest way to check your battery strength is to look at the voltage pane in your IrriMAX software system. The voltage at each upload interval is denoted by a red cross. Your battery is reaching the end of its life if voltage readings are consistently recorded at 12v or lower.

The maximum distance we recommend between an SDI-12 interface and your data logger is 60 metres with 22AWG/3 conductor specification.

The maximum distance we recommend for use with an RS485 interface is up to 1 kilometre with 26AWG twisted pair with correct termination.

The maximum distance we recommend for use with an RS232 interface is 5 metres as tested by Sentek at a 9600 baud rate. We do not support systems modified beyond this tested configuration.