Endress+Hauser WirelessHART Fieldgate SWG70, Руководство по эксплуатации

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Function and system design WirelessHART Fieldgate SWG70
14 E Hauser
3.3 Connecting to HART-compatible host systems
Fieldgate SWG70 also makes wireless communication accessible to HART-capable host sys-
tems via its Ethernet interface or serial interfaces (RS-485) and the following functions.
Depending on the version ordered, Fieldgate SWG70 can also be integrated into Modbus,
OPC or Ethernet/IP host systems.
3.3.1 Instrument list
The WirelessHART devices in the network are made available to the host systems via an
instrument list. This list contains one or more I/O cards. Every I/O card has one or more
channels. Up to 6 field devices can be connected in multidrop mode to each channel. See
Figure 3-3 on page 14. The list itself can be up and downloaded. See Chapter 10.1 "Instru-
ment List" on page 64.
Fieldgate SWG70 assigns a virtual I/O card to each WirelessHART device. The I/O cards are
assigned to the WirelessHART devices in the order in which they join the network. New
WirelessHART devices in the network are assigned to the next available I/O card, which is
added to the end of the instrument list (First-in-First-Out principle).
Within an I/O card, the WirelessHART device itself as well as status information is assigned
to Channel 0. If the WirelessHART device is an adapter, all field devices connected to it are
assigned to channel 1 (multi-drop mode). The list of the connected field devices is also called
sub-device list.
Fig. 3-3: Instrument list
If a WirelessHART device loses communication to the Fieldgate, it stays assigned to the I/O
card initially allocated to it. When communication is established again, the device thus has
the same position in the instrument list that it had before.
The same principle applies to the field devices connected to the WirelessHART Adapter
(SWA70). When communication to the Fieldgate is lost, the long tags of the filed devices are
stored. After communication has been established again, the field devices regain their pre-
vious position in the instrument list.
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2
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WirelessHART-Gateway
I/O card 1
I/O card 2
Channel 0
WirelessHART Field device
WirelessHART Adapter
Channel 0
Channel 1
WirelessHART Field device1
WirelessHART Field device2
WirelessHART Field device3
Network structure
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Instrument list I/O structure