Siemens SIMATIC RF600 Series System Manual page 25

The horizontal line at 41.25 V/m marks the "safety limit value".
Distance to transmitter antenna [m]
If the transmit power is set lower than the highest permitted value (4 W EIRP), the "safety
distance" reduces correspondingly.
The values for this are as follows:
Generally a safety distance of at least 0.2 m should be maintained.
RF650R/RF680R/RF685R-specific notes
Note
Reduced maximum radiated power with RF650R/RF680R/RF685R readers
The SIMATIC RF650R (FCC) reader has a maximum transmit power of 1 W. The radiated
power therefore depends on the antenna cable and the type of antenna used, but must not
exceed 4 W EIRP.
The SIMATIC RF680R (FCC) reader has a maximum transmit power of 2 W. The radiated
power therefore depends on the antenna cable and the type of antenna used, but must not
exceed 4 W EIRP.
The SIMATIC RF685R (CC) reader has a maximum transmit power of 2 W. This means that
the safety distance is at least 0.12 m.
When using Siemens products and with suitable configuration via the WBM, the high limits
cannot be exceeded.
SIMATIC RF600
System Manual, 10/2016, J31069-D0171-U001-A19-7618
1
5
Radiated power EIRP [W]
4.0
<2.5
2.3 Safety distance to transmitter antenna
Feld strength [V/m]
10.9
2.2
Safety distance to transmitter antenna [m]
Safety Information
% of limit value
26
5.3
0.26
>0.20
25