Field Bus

VCR(Virtual communication relationship) 1. client/server VCR Used for queued, user-initiated, and one-to-one

communication between devices on the fieldbus.Queued means that messages are sent and received in the order submitted for transmission, according to their priority, without overwriting previous messages.

Conti……

When a device receives a pass token (PT), it may send a request message to another device on the fieldbus.

The requester is called the “client,” and the device that received the request is called the “server.”The server sends the response when it receives a PT

Field Bus

Used for operator-initiated requests such as set point changes, tuning parameter access and change, alarm acknowledgment, and device upload and download.

2. Report distribution VCRUsed for queued, user-initiated, one-to-many communications.

Conti…. Field Bus

When a device with an event or a trend report receives a pass token (PT) it sends its message to a “group address” defined for its VCRDevices that are configured to listen on that VCR will receive the report Fieldbus devices to send alarm notifications to

the operator consoles typically use the report distribution VCR type.

Field BusConti….

Field BusConti…. 3.publisher/subscriber VCRIt is used for buffered, one-to-many communicationsBuffered means that only the latest version of the data is maintained within the network.New data completely overwrite previous data.When a device receives the complete data (CD), the device will “publish” or broadcast its message to all devices on the fieldbus. Devices that wish to receive the published message are called “subscribers.”

Field BusConti….

Field Devices for Pressure measurement

Flow measurement devices

Temperature Devices

The FVX110 field mount indicator is fully compliant with the FOUNDATION™ fieldbus digital communications protocol.

With a single FVX110, up to 16 process variables from multiple field instruments can be monitored

Reduces Plant instrumentation costs.

The YVP110 Advanced Valve Positioner accepts digital communication to control a pneumatic actuator mounted to a control valve.

It communicates using the FOUNDATION™ fieldbus protocol.