Fieldbus Configurator Questions on Downloads, VFDs, Synchronization and Failover Primary Software: Driver Software>>NI-FBUSPrimary Software Version: 2.3.5 Primary Software Fixed Version: N/A Secondary Software: N/A
Problem: 1. What granularity is supported when I download a Fieldbus segment or device? Can the whole segment be downloaded at once? Can devices be individually downloaded? Can a function block in a device be relinked without downloading the whole device? 2. Does the system support field devices that have multiple Virtual Field Devices (VFDs) that represent their function block application? 3. Is synchronization time between the control system and the Fieldbus supported? If so, what accuracy is specified? 4. If there is a failover from one Link Active Scheduler (LAS) to another, how is this handled? Solution: 1. The entire schedule and function block application is downloaded at one time. Devices can not be individually downloaded. To relink a function block in a device, you have to download the entire application. 2. If a device has multiple Virtual Field Devices (VFDs), the National Instruments Configurator would be able to use the function blocks in the VFDs. A VFD describes the application in the device. 3. So long as the control system has a Fieldbus interface and can become a device with Link Master capabilities on the segment, then time synchronization is supported. Time is periodically broadcast over the network by a time master device. The time distribution period is a Management Information Base (MIB) parameter that is configurable. 4. Failover is handled transparently. When the LAS fails, another link master device on the same link becomes the LAS and takes over the scheduling duties provided it received the schedule during download. See KnowledgeBase entry 1AECJRUB for more details. Related Links: Attachments:
Report Date: 09/22/1998 Last Updated: 06/30/2004 Document ID: 1DL8MFL7 |
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