Chapter 8
Servers
8-2
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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.
