OPERATION MANUAL CompoBus/S

System Configuration Section 2-2
Restrictions on
Connections
26
The following restrictions apply to CompoBus/S connections:
System with Distinction between Main and Branch Lines
The following diagram shows a CompoBus/S System configuration in which
the main line must be distinguished from the branch lines under either of the
following conditions.
The system operates in High-speed Communications Mode.
The system operates in Long-distance Communications Mode with 2-conductor
VCTF cable.
Master
Communications
Power
Supply
Communications Cable
Slave Slave
Slave Slave Slave
Slave
Terminator
Main line T: T-branch connection
Branch line M: Multidrop connection
Power supply cable
(Communications power is supplied to each Slave
separately when 2-conductor VCTF cable is used.)
The main line is the cable that connects the ends of the system. The maximum
length of the main line depends on the communications mode, the
type of cable, and the number of Slaves being used. Refer to 2-2-2 Maximum
Cable Length for details.
A branch line is any cable that branches off the main line. The maximum
length of a single branch line and the maximum total length of all branch
lines in a CompoBus/S system vary according to the communications
mode, the types of cables used, and the number of Slaves. Refer to 2-2-2
Maximum Cable Length for details.
The Master must be connected at one end of the main cable and the terminator
must be connected at the other end. The Master cannot be connected
at a point along the main line or on a branch line.
Only one Master can be connected in the CompoBus/S System. The
range of usable node numbers that can be connected depends on the
model of Master being used and its settings. Refer to 2-1 Communications
Specifications for details.
Only one Slave can be connected to each branch line. It is not possible to
branch again from a branch line.
There are three types of cable that can be used (2-conductor VCTF cable,
4-conductor VCTF, and Special Flat Cable), but it is not possible to use
more than one type of cable in the same CompoBus/S System.
System with No Distinction between Main and Branch Lines
The following diagram shows a CompoBus/S System configuration in which
no distinction is required between the main line and the branch lines under
either of the following conditions.
The system operates in Long-distance Communications Mode with 4-conductor
VCTF cable
The system operates in Long-distance Communications Mode with Special
Flat Cable