HIMA HIMax, Системное руководство

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HIMax System 3 Product Description
HI 801 001 E Rev. 4.01 Page 25 of 122
The HIMax system measures the actual system bus latency during operation and displays it
in the SILworX Control Panel.
3.2.3.1 Default Values for the Maximum System Bus Latency
The HIMax system uses the system bus maximum latency default values in the following
cases:
ƒ The parameter Maximum System Bus Latency [µs] is set to 0.
ƒ The project was created with a SILworX version prior to 4.
For a HIMax System, exclusively composed of HIMax components with maximum 100 m
copper cables for each two base plate connection, the maximum system bus latencies by
default corresponds to the following table:
Maximum base
plate distance Maximum system bus latency Example: the system consists of the
mentioned base plates
0 56 µs Only Rack 0
1 116 µs Racks 0 and 1
2 179 µs Racks 0, 2, 4
3 242 µs Racks 0, 1, 3, 5
4 305 µs Racks 0, 2, 4, 6, 8
5 368 µs Racks 0, 1, 3, 5, 7, 9
6 431 µs Racks 0, 2, 4, 6, 8, 10, 12
7 494 µs Racks 0, 1, 3, 5 , 7, 9, 11, 13,
8 557 µs Racks 1, 0, 2, 4, 6, 8, 10, 12, 14
Table 8: Default Values for Maximum System Bus Latency
HIMax uses these maximum system bus latency default values calculated automatically,
irrespective on whether the line or network structure has been set up.
System Bus Extension for the Max. Latency Default Settings
Already if the maximum system bus latency is set to the default value 0, the system bus
can be extended over a long distance using fiber optic cables. The cable length is limited
due to the signal delay in the fiber optic cable and in the converters between Ethernet cable
and fiber optic cable.
HIMax allows for default latency, the following maximum additional delay time between
modules:
ƒ Among redundant processor modules: max. 10 µs.
ƒ Between a processor module and the furthermost I/O module: max. 50 µs.
The use of a fiber optic cable causes the following delays:
ƒ Total delay due to converters "copper cable - fibre optic cable - copper cable": 1 µs.
ƒ Delay within the fiber optic cable, e.g., 5 µs/km.
The delay due to the short copper cables between system bus modules and converters
corresponds to the delay of the fiber optic cable. The length of these copper cables is
included in the total length.
All processor modules are located close to one another, i.e., either in rack 0 or distributed
among rack 0 and rack 1, which are connected via one (short) copper cable. The two
furthermost racks with I/O modules can then be located up to 9.8 km from the processor
modules.
The HIMax system can have a maximum extension of up to 19.6 km (Figure 5).