Radio systems


The HFU 700 device group is a system for the wireless transmission of temperature and moisture values. Thermocouples and resistance sensors are used as sensors. In this way, customer-specific solutions can be implemented in conjunction with different sensors. Data transmission takes place in the 2.4 GHz range. A star-shaped wireless personal area network (WPAN) is built up. The wireless modules used work in accordance with the IEEE802.15.4 standard for low-rate WPANs.

Networks can be set up with up to 240 transmitter modules with one receiver. 2 wireless actuators can be used to increase the range. The networks can also overlap without interfering with each other. These sensors are intended to be used for carrying out measuring tasks in cases where wiring would be disruptive or impossible. Possible applications are, for example, measuring the temperature at rotating and mobile parts or for fermenting and smoking processes in the food industry. Wireless solutions are also practical when renovating existing applications. The receiver is supplied with 24 V. The transmitters work with a lithium battery (3.3 V); these batteries have a lifespan of up to 2 years, depending on the necessary transmit rhythm. The transmitting capacity amounts to a max. 10 mW. It is thus possible to bridge distances of 50 to 300 m (depending on the terrain or constructions). Through the use of actuators, these can be further increased. Data transmission takes place bidirectionally, resulting in the high degree of interference resistance and availability of the network.


HFU 721 wireless receiver

For the analysis, a HFU 721 receiver (top-hat rail mounting) is available. It has 4 analogue outlets (0..10V / 4-20mA) and a RS485 / RS232 outlet (switchable).

With the help of the analogue outlets, smaller networks can also be set up inexpensively, without the use of additional computer technology.
Via two integrated relays, the battery voltage and a freely adjustable threshold value can be monitored and, if need be, signalised.


HFU 722 wireless transmitter with connection head.

The HFU 722 is a universally programmable temperature wireless transmitter which is already mounted in a connection head and is delivered with an antenna and a lithium battery.

It can be programmed to Pt100 / Pt1000 or a variety of thermocouples.
The head can be adapted to a wide variety of sensors for a wide range of applications.


HFU 726 wireless transmitter for integration into the case

The HFU 726 is a universally programmable temperature wireless transmitter for integration into different casings.
The technical data corresponds to the HFU 722.

In this model, any temperature sensor can be connected to the transmitter through a cable link. This makes customised solutions possible.

HFU 725 outside temperature sensor HFU 725

The HFU 725 outside temperature sensor serves to measure the air temperature. It is also available in a version with additional moisture measurement (HFU 725 FT). The level of protection is IP 65. It can be used for new installations; however, it is also very suitable for retrofitting purposes if new installations using cable links are undesirable (e.g. churches and museums).

Antenna extension cables, magnet foot antennae, spare batteries, as well as data and programming cables are available as accessories for the assembly groups.
The analysis software EasyWPAN 700 is freely available.