Bus Topology With Combricks; Star/Hub Topology With Combricks; Delay Time - Procentec ComBricks User Manual

Fiber optic communication is in all situations point-to-point where the receiver and transmitter wires are
crossed. The combination of modules can create complex topologies like; bus and star/hub topologies. Every
topology has its own advantages and disadvantages.
9.1.1

Bus topology with ComBricks

•
Long delay time
•
Long range possible (cascading)
•
Extendable only at the ends (without adding new modules)
9.1.2

Star/Hub topology with ComBricks

•
Relative short delay time (no busparameter adjustments required)
•
Adjustable at any time
•
More module are required
•
High availability

9.2 Delay time

Fiber optic applications require a delay time calculation to adjust the Slottime busparameter in the
configuration of the master(s). ComBricks complies with the following formulas:
FO cable delay = ( 5 ∗ 10
Example: 1.5 Mbps, 3 km FO cable
FO cable delay = 0.000005 × 3 × 1500000 = 22.5 TBit
Tdelay = (FO cable delay + ( 2 × Module delay time) ) × 2
Continued example: 1.5 Mbps, 22.5 TBit FO delay:
Tdelay = (22.5 + ( 2 × 1.8 ) ) × 2 = ����. �� TBit
This is between 2 fiber optic modules! More calculations have to be done when more modules are involved
(see Fig. 58).
The total delay for the entire network has to be added to the Slottime setting in the busparameters of the
master.
ComBricks User Manual v6.4.0 | January 18| © PROCENTEC
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) × FO cable length × Baudrate
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