Flowserve MX FOUNDATION Fieldbus Field Unit Instrukcja Użytkownika Pobierz pdf (Strona 8)

MX/QX FOUNDATION Fieldbus Field Unit FCD LMENIM2330-01 – 08/11

1.5.1 General Network Speciﬁcation

System Speciﬁcations:

• Communicates using the FOUNDATION ﬁeldbus protocol

• Employs high-speed communication

• Complies with the IEC61158 ﬁeldbus standard.

Network Speciﬁcation

Several topologies are available, point-to-point, bus with spurs, daisy chain, tree, or a combination of

these. Network features include:

• Link Active Scheduler controls the system

• High-speed communications up to 31.25 kbits/s

• Peer-to Peer communication.

MX/QX FF Field Unit Speciﬁcation

The ﬁeld unit mounts in the actuator and is software controlled in order to allow functionality of:

• Input and Output Function Blocks

• Proportional Integral Derivative (PID) Function Block

• Device descriptions

• Network communication

• Parameter conﬁguration by user.

Link Active Scheduler Speciﬁcation

Fieldbus segments have one, and only one, active Link Active Scheduler (LAS) at a given time. The

LAS acts as the bus arbiter, and does the following:

• Recognizes and adds new devices to the link

• Removes non-responsive devices from the link

• Schedules control activity in, and communication activity between, devices

• Regularly polls devices for process data

• Distributes a priority-driven token to devices for unscheduled transmissions.

System Host Speciﬁcation

The system host is usually a distributed control system (DCS), or some other intelligent device. The

host does the following:

• Acts as the system LAS

• Issues requests for process data from the ﬁeld devices

• Issues commands to the ﬁeld devices

• Interfaces with any process control going on between network devices.

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Flowserve MX FOUNDATION Fieldbus Field Unit Instrukcja Użytkownika Strona 8