Emerson Smart Wireless Gateway 1420, Справочное руководство

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C DeltaV
™
Ready
C.1 Overview
Native integration with DeltaV enables the Emerson
™
Wireless 1420 Gateway (Gateway) to
be autosensed and easily commissioned for seamless integration with all DeltaV
applications: Explorer, Diagnostics, and Control Studio. WirelessHART
®
devices can be
easily added to the wireless field network and then reconciled through DeltaV Explorer and
assigned to analog channels through drag and drop assignment.
C.2 Latency considerations in control logic design
and operation
Since the DeltaV wireless I/O scanner software requests updates for of the devices each
second, DeltaV receives updates on a particular field device once every five seconds. That
is not necessarily synchronized with the update rate of the field device. Also, there is some
latency between when the field device takes a process sample and when it is permitted to
pass its value onto the wireless network. Status update responses can also increase latency
in some instances. So for example, if a device updates once every eight seconds, and
wireless network latency is two seconds, the amount of time that could pass between
when an event occurred in the field and before it is available to the DeltaV I/O bus is
between zero and 15 (8+2+5) seconds. The update period of the DeltaV control module
should be added to that total to determine the range of latencies before an event in the
field can be acted upon by the control system.
Operators should be made aware that the update rate of wireless measurements on
operator screens are somewhat slower than those from wired devices. For example, if the
operator initiates a valve movement, it can be five to 15 seconds before confirming
feedback appears on the operator screen. Any control logic designed along the same
principles should also take the update rates and latencies into account as well.
C.3 Requirements
DeltaV
Version 10.3 or newer.
Gateway
DeltaV Ready option (Data Protocol option 5). See Ordering information .
C.4 Mounting and connecting
Mount the DeltaV Ready Gateway in the same manner as a standard Gateway. ( Mounting ).
The Gateway should be mounted in a location that allows convenient access to the DeltaV
control network as well as the wireless field network.
Reference Manual DeltaV
™
Ready
00809-0200-4420 September 2020
Emerson.com/Rosemount 79