CNGmass
Electrical connection
Hauser
17
7
Electrical connection
The measuring device does not have an internal circuit breaker. For this reason, assign
the measuring device a switch or power-circuit breaker so that the power supply line can
be easily disconnected from the mains.
7.1
Connection conditions
7.1.1
Required tools
• For cable entries: Use corresponding tools
• For securing clamp (on aluminum housing): Allen screw3 mm
• For securing screw (for stainless steel housing): open-ended wrench 8 mm
• Wire stripper
• When using stranded cables: crimping tool for ferrule
7.1.2
Requirements for connecting cable
The connecting cables provided by the customer must fulfill the following requirements.
Electrical safety
In accordance with applicable federal/national regulations.
Permitted temperature range
• –40 °C (–40 °F) to +80 °C (+176 °F)
• Minimum requirement: cable temperature range ≥ ambient tempe20 K
Power supply cable
Standard installation cable is sufficient.
Signal cable
Modbus RS485
The EIA/TIA-485 standard specifies two types of cable (A and B) for the bus line which can be
used for every transmission rate. Cable type A is recommended.
Cable type
A
Characteristic impedance
135 to 165 Ωat a measuring frequency of 3 to 20 MHz
Cable capacitance
<30 pF/m
Wire cross-section
>0.34 mm
2
(22 AWG)
Cable type
Twisted pairs
Loop resistance
≤110 Ω/km
Signal damping
Max. 9 dB over the entire length of the cable cross-section
Shielding
Copper braided shielding or braided shielding with foil shield. When grounding the
cable shield, observe the grounding concept of the plant.
