SMA PT100U-NR - Manual (Page 8)

Installation and Electrical Connection SMA Solar Technology AG
8 PT100UNR-IEN083510 Installation Guide
4 Installation and Electrical Connection
The PT100U ambient temperature sensor can be connected to the Sunny Boy Control Plus or the
Sunny Central Control via a 2- or 4-wire system as desired. The connection cable is not included and
is routed into the enclosure interior via a cable gland.
4.1 Cabling Recommendations
The cable length and quality will affect the signal quality. To achieve a good quality signal, observe
the following cabling instructions:
Outdoors
For outdoors, use a cable with the following basic properties.
• Cross-section: min. 4 x 0.25mm², min. 4 x AWG 24
• External cable diameter: min. 4.5mm, max. 7mm
• UV-resistant
We recommend the following cable types:
• Lapp cable: Unitronic S-LifY11Y 4 x 0.34mm², order no.: 7038 861
• UL-listed Lapp cable: UNITRONIC S-LifY11Y 4 x 0.34mm², order no.: 7038 865
2-wire system
When connecting the temperature sensor in a
2-wire system, the cable resistance is included in
the measurement. Depending on the cable
length, this can lead to inaccuracies when
measuring.
The 2-wire system should therefore only be used with short cable lengths (maximum 3m)
or where the necessary degree of measuring accuracy is not as high. In order to improve
the measuring accuracy, the use of a 4-wire system is recommended.
4-wire system
To offset measuring errors that occur due to
cable resistance, connect the temperature
sensor via a 4-wire system. This type of
connection ensures the current feed and voltage
measurement are performed by separate pair cables. The length of the cable must not
exceed 30m.