National Instruments BridgeVIEW 用户手册

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Chapter 8
Servers
8-2
© National Instruments Corporation
The device servers also handle and report communications and device 
errors to BridgeVIEW. There are different servers available for different 
device families and communication networks. 
Each device server is a stand-alone component that might include a 
configuration utility as well as the run-time application that communicates 
with the BridgeVIEW Engine. IA Device Servers are not built into the 
BridgeVIEW Engine itself. These servers are written to a National 
Instruments standard client/server Applications Programming Interface 
(API) for communicating with the BridgeVIEW Engine and the Common 
Configuration Database.
When BridgeVIEW runs an application, it determines from the tag 
configuration (.
scf
) file which servers are needed, and which items are 
needed from those servers. BridgeVIEW launches each server it needs, 
and notifies each one to monitor the specific items of interest. Typically, 
servers monitor each input tag on a regular basis, passing the values to 
the BridgeVIEW Engine when they change, and updating each output tag 
when the BridgeVIEW HMI application writes that tag value. The update 
rates and deadband servers use for monitoring items can be configured as 
part of tag configuration. You define how a server monitors the items, how 
often it polls the devices, and other server-specific and device-specific 
parameters through each device server configuration utility.
How Do You Install and Configure a Device Server?
BridgeVIEW works with several device servers including the NI-DAQ 
OPC Server, the device servers available on the BridgeVIEW Device 
Servers CD, and the simulation servers installed with BridgeVIEW. 
In addition, you can use other servers available from companies other than 
National Instruments.
To use a device server with BridgeVIEW, first you must install the device 
server and register it or run its configuration utility. More specific 
information on installing and registering National Instruments servers 
follows later in this section. This information is written to the Common 
Configuration Database, where BridgeVIEW obtains the server 
information. For some servers, you configure devices and items with the 
server-specific Configuration Utility. Then, the Tag Configuration Editor 
imports server, device, and item information so you can create tags. IAK 
device servers allow you to directly create and configure communication 
resources, devices, and items from the Tag Configuration Editor.