Endress+Hauser WirelessHART Fieldgate SWG70, Руководство по эксплуатации

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Function and system design WirelessHART Fieldgate SWG70
12 E Hauser
3 Function and system design
3.1 WirelessHART protocol
The HART protocol has until now used the wired 4–20 mA loop with a superimposed digital
signal as physical layer.
WirelessHART enables the wireless transmission of HART data. To be employable world-
wide, WirelessHART utilizes the 2.4 GHz Band (IEEE 802.15.4 wireless network) as physical
layer. The WirelessHART devices form a mesh network in which every device is not just a
measurement point, but also a repeater. This results in a wider range for the whole network
as well as increased reliability through redundant communication paths.
The network may comprise three types of device:
• WirelessHART gateway (Fieldgate SWG70)
• WirelessHART field devices
• WirelessHART Adapters (SWA70): either connected to 4–20 mA/HART devices or acting
as repeaters.
The WirelessHART network is built up, organized and maintained by the Fieldgate, which
also takes care for connection to different HOST systems through different bus interfaces.
Fig. 3-1: WirelessHART network
1 Host applications
2 Ethernet 3 WirelessHART Fieldgate
4 Field devices with wireless
Ethernet
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