Coaxial Bus System - Mitsubishi Electric Melsec QJ71LP21 Reference Manual

4 SETUP AND PROCEDURES BEFORE STARTING THE OPERATION

4.6.2 Coaxial bus system

4 - 22
(1) Precautions for connecting
(a) Restrictions on the cable length between the stations
1) When connecting between the network modules, the cable lengths
indicated in the table below must be used according to the number of
stations connected.
A communication error may occur if a cable length is out of the
following ranges.
Number of stations connected
Station-to-station cable length
Cable type
0 to 1 m (3.28 feet)
1 (3.28 feet) to 5 m (16.41 feet)
5 (16.41 feet) to 13 m (42.65 feet)
13 (42.65 feet) to 17 m (55.78 feet)
17 (55.78 feet) to 25 m (82.03 feet)
25 (82.03 feet) to 300 m (984.3 feet)
300 (984.3 feet) to 500 m (1640.5 feet)
2) If there is a possibility of adding stations to extend the system, cables
considering restriction 1) mentioned above.
3) When using a repeater module (models A6BR10 or A6BR10-DC), only
the length indicated in "10 to 33 stations" can be applied regardless of
the number of stations connected or the number of repeater modules.
(b) Cable installation precautions
1) Install the coaxial cables at least 100 mm (3.94 inches) away from
other power cables and control cables.
2) Consider to use double-shielded coaxial cables in locations where
there is excessive noise.
Double shield coaxial cable
Mitsubishi Cable · · · 5C-2V-CCY
5C2V connector plug can be applied to double-shielded coaxial cable.
Connect the plug to the coaxial cable inside the double-shielded
coaxial cable.
Ground the shielded section, external part of the double-shielded
coaxial cable, as shown above.
Locate external conductor (ground) of the double-shielded cable
approximately 10mm away from the connector plug for 5C2V. (Do not
contact them.)
2 to 9 stations
3C – 2V 5C – 2V
(cable less than 1m (3.28 feet) in length cannot be used.)
Ground
External conductor (ground)
Sheath Sheath
Approximately 10mm
MELSEC-Q
10 to 33 stations
5C-FB 3C – 2V 5C – 2V
: Allowed : Not allowed
Cable close-up
Internal Insulator
conductor
Sheath
External
External
conductor
conductor
(ground)
5C-FB
Sheath
4 - 22