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EKM-E ETHER-MON KEY DE-211
EZ7 RS485 Wiring
How many EZ7 RS485 devices may be installed on one network trunk?
Up to 52 devices may be installed on a network string (EZ7 RS485 only) read with E-MonEnergy software.
What wire gauge do you need?
Unterminated networks with current less than 10 mA; we recommend 20 AWG to 22 stranded twisted pair with a shield.
How long can the cable be?
Under ideal conditions and default baud rates of 9,600, cable lengths of 4,000 feet (~1200 meters) is possible. However,
the cable recommended for long lengths can be expensive. So if there is an existing Ethernet infrastructure in place it
may be more affordable to convert from EZ7 RS485 to EZ7 Ethernet. Please consult with your system integrator for
communication device options.
What should the cable impedance and capacitance be?
Cables suitable for use in an RS-485 network should have an impedance of between 100 and 130 ohms, a capacitance
between conductors of less than 30 pF per foot (100 pF per meter), and a capacitance between conductors and shield
less than 60 pF per foot (200 pF per meter.)
Can you run the RS-485 network cable adjacent to or in the same conduit with load bearing feeders?
We strongly recommend against this. There may be interference from the high voltages and currents present on the
mains wires, and if there is any insulation fault, arcing, etc. on the mains wires, it could put dangerous voltages on the
low-voltage RS-485 network cable.
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