Endress+Hauser NRF81 - Connecting Requirements and Cable Specifications

Tankside Monitor NRF81 Electrical connection
Endress+Hauser 33
6.2 Connecting requirements
6.2.1 Cable specification
Terminals
Terminal Wire cross section
Signal and power supply
• Spring terminals (NRF81-xx1...)
• Screw terminals (NRF81-xx2...)
0.2 to 2.5 mm
2
(24 to 13 AWG)
Ground terminal in the terminal compartment max. 2.5 mm
2
(13 AWG)
Ground terminal at the housing max. 4 mm
2
(11 AWG)
Power supply line
Standard device cable is sufficient for the power line.
HART communication line
• Standard device cable is sufficient if only the analog signal is used.
• Shielded cable is recommended if using the HART protocol. Observe the grounding
concept of the plant.
Modbus communication line
• Observe the cable conditions from the TIA-485-A, Telecommunications Industry
Association.
• Additional conditions: Use shielded cable.
V1 communication line
• Two wire (twisted pair) screened or un-screened cable
• Resistance in one cable: ≤ 120 Ω
• Capacitance between lines: ≤ 0.3 µF