4. Appendix
4-12
TI 30A10A05-01E
Dec. 26, 2016-00
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Vnet/IP in the Ring network
When applying the ring network to the Vnet/IP, following points must be considered.
(1) Limitation in network delay
In the Vnet/IP’s communication among the domain, the delay in the network between any
two of the stations has to be designed as 1 msec or less. Therefore, even a failure occurs at
any point on the ring network, the delay time should not exceed 1 msec. As described in the
GS, the network delay is within the limitation when up to 7 levels of L2SWs are connected in
the overall cable length of 40 km or less. In case of configuring a large scale communication
network by the ring topology, contact Yokogawa in advance.
(2) Detecting a single failure on network
Failure monitoring function of the Vnet/IP is implemented by monitoring the communication
status among stations. When a failure occurs in the ring network and the network device
itself switches the communication route to the redundant path, the failure is not detected
by CENTUM System because the communication status between the stations does not
change. As a countermeasure, CENTUM system has to be engineered to adopt a FAULT
output terminal as a DI signal in the FCS to generate alarms.
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Requirements for Vnet/IP Ring network
l
Network switch
The table below shows the list of Vnet/IP network switches applicable for structuring a ring
network. Do not use any other switches for the ring networks.
Table Vnet/IP network switches applicable for Ring network
Layer
Vnet/IP Bus
MS-Code (Vender model name)
Product Family
L2SW
Bus 1
Bus 2
GRVSW-660FA RS40-0009CCCCEDBPYY
RS40
GRVSW-663FA MACH104-20TX-F
MACH104
GRVSW-664FA MACH104-20TX-FR
GRVSW-665FA MAR1040-4C4C4C4C9999EM9HPYY
MAR1040
GRVSW-666FA MAR1040-4C4C4C4C9999EMMHPYY
GRVSW-667FA MAR1040-4C4C4C4C9999ELLHPYY
L3SW
Bus 1
GRVSW-668FA MAR1040-4C4C4C4C9999EM9HRY1
GRVSW-669FA MAR1040-4C4C4C4C9999EMMHRY1
GRVSW-670FA MAR1040-4C4C4C4C9999ELLHRY1
Bus 2
GRVSW-671FA MAR1040-4C4C4C4C9999EM9HRY2
GRVSW-672FA MAR1040-4C4C4C4C9999EMMHRY2
GRVSW-673FA MAR1040-4C4C4C4C9999ELLHRY2
Notes: MACH102, which is fit for a small-scale system, is not applicable for a ring network.
Use the Vnet/IP network switch firmware revision of “Software Release 09.0.06” for the ring
network.
Summary of Contents for Vnet/IP
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