FANUC Robotics America GFK-1535A - Manual (Page 35)

2-16 VersaMax™ System Genius® Network Interface Unit User's Manual – November 2000 GFK-1535A
2
NEC classes are based on data obtained from manufacturers and are subject to
change. CANADIAN CEC codes are similar. Other countries may vary.
The serial bus can be treated as a Class 2 circuit when appropriate wiring practices
are followed. Maximum available bus lengths may be affected when installation
requires the high voltage CM (Communications) rating. CM types can replace CL2,
but not vice versa.
Do not mix cables of different impedance, regardless of cable run length. Do not
mix cable types in long and/or noisy installations. Other, small-size twisted pair
shielded wire of unspecified impedance can be used for short runs of 50 feet or less,
using 75 ohm terminations. Selection of wire type may be limited by local and
national codes and industry standards. Consult the cable manufacturer to determine
the cable's suitability for a particular type of installation.
Conservative wiring practices and national and local codes require physical
separation between control circuits and power distribution or motor power. Refer to
sections 430 and 725 of the National Electric Code.