SARAD GmbH
17
Manual_Smart-Radon-Sensor_EN_12-03-2020.docx
Alert switch
The Smart Radon Sensor is equipped with a switch output which can be used for ventilation control
or alert indication. The potential-free contacts of the switch will be short-circuited at the end of the
sampling interval if the measured Radon concentration exceeds the alarm threshold. The output will
be deactivated one minute before the subsequent interval ends. Therefore, the sampling interval
must be set at least to two minutes. The alarm threshold is factory-set to 300Bq/m³ (statutory
reference value of the Radiation Protection Act) and may be changed by the user with respect to
local regulations (instrument setup in Radon Vision). Warning: at the same time the alarm threshold
defines the Radon range for the maximal output signal of the current loop. Please refer to the
previous chapter: „Analogue output”.
The terminal ports for the alert switch are designated in figure 2 and table 1.
As an accessory, we offer a wireless power switch which can be used for direct ventilation control.
The switch includes a transmitter unit to be connected to the alert switch output of the instrument,
and a plug adaptor (receiver) which can be placed between the wall outlet and the power cable of
the ventilation unit. Optionally, a flush-mounting power switch is also available. The plug adaptor
offers an additional timer function to define the duration of the ventilation period independent from
the sampling interval of the instrument (for example 15 minutes ventilation while the sampling
interval is 60 minutes long). The wireless switch is coded - that means, several transmission lines can
be established within one building. The assignment between transmitter and receiver is easily done
by a push button.
The sampling interval should be set to a value between 60 or 120 minutes for an alarm threshold
lower than 300Bq/m³.