Siemens SIMATIC RF600 Series System Manual page 389

Ignitions of dust-air mixtures
Using the RF680T transponder with radiant power greater than 1280 mW ERP, requires
compliance with the reduced maximum ambient temperature (see diagram) for maintaining
the temperature value to a maximum of 135 °C. Non-compliance with the permitted
temperature ranges while using the transponder can lead to ignitions of dust-air mixtures.
The respective temperature value and the maximum allowed ambient temperature in relation
to the radiated power of the antenna is shown in the diagram below:
Figure 7-38
SIMATIC RF600
System Manual, 10/2016, J31069-D0171-U001-A19-7618
WARNING
Temperature value
Ambient temperature
Temperature value and maximum permitted ambient temperature in relation to the
radiated power
Transponder
7.14 SIMATIC RF680T
389