RainWise PVmet 500 Series User Manual page 15

The only BOM sensors supported are provided by RainWise and they are 10K PTC thermistors in an aluminum housing. No other
temperature sensors are supported at this time. The sensors are purely resistive, so the electrical connections are reversible. The cable
for the BOM sensor is shielded for noise reduction and to protect from ESD/EMI. The shield is not connected at the sensor end it is
only to be connected at one point, directly at the main board using the 360° shield connector which is internally connected to the
earth ground connection. Notice how the shield wire is wrapped around the sheath of the cable in Figure 17.
Figure 17: Typical BOM wire end and wire end with wrapped shield
The 360° shield spring clamp provides a solid shield connection and a good path for dissipating noise and transients. To attach the
cable simply press the cable with wrapped shield into the spring clamp as shown in Figure 18.
Figure 18: BOM cable inserted into 360° shield connection
Properly connecting the shield is important for sensor accuracy and system protection. If the BOM sensor is located too far from the
PVmet-500for the included length of cable an extension cable can be used if the shield is connected and not connected to ground
except at the PVmet-500360° shield connector. Changing the length of the cable will cause an error in the temperature reading. To
counter the added error of a longer cable a temperature derating factor of -0.041 C° per meter of extended cable. Table 1 shows some
common examples of temperature correction.
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