Glossary of Terms:
Automatic (AUTO) A possible mode of a function block which means the block runs its
algorithms, producing data at its inputs or outputs.
Basic Device A basic device is any device not having the capability to control
communications on an H1 fieldbus segment.
Back calculation output This parameter is available on output function blocks, and provides a
(BKCAL_OUT) feedback mechanism to control blocks such as PID.
Capabilities File A file describing the communication objects in a fieldbus device. A
configuration device can use Device Description (DD) Files and
Capabilities Files to configure a fieldbus system without having the
fieldbus devices online.
Cascade (CAS) A possible mode of a function block which refers to an input derived
from the output of another function block.
Device Description (DD) A machine-readable description of all the blocks and block parameters
of a device.
Fieldbus The digital, two-way, multi-drop communication links.
Fieldbus Interface Card (FIC) The option card fitted to the actuator which provides the
communications interface between the DCS and the actuator.
Function Block (FB) Also known as standard function block. This is a named block
consisting of one or more inputs and outputs. These are built into
fieldbus devices to achieve the desired control functionality. The FF
CP has Analogue Input (AI), Analogue Output (AO), Digital Input (DI),
Digital Output (DO), Control Selector (CS) and PID control (PID).
H1 A term used to describe a FF highway operating at 31.25 kbit/sec.
Initialization Manual (IMAN) The forward path to a physical output is broken and the output is
tracking the downstream block. This will result in the control action
being suspended.
Interoperability The capability for a device from one manufacturer to interact with that
of another manufacturer, on a fieldbus network, without loss of
functionality.
Input / Output Options This parameter is contained within output function blocks and
(IO_OPTS) allows different parameters to appear at various connection points.
Link Active Scheduler (LAS) One Link Master (LM) device functions as the fieldbus LAS at any one
time. The LAS is the Fieldbus device that is currently controlling
access to the Fieldbus. A device that is responsible for keeping a link
operational. The LAS executes the link schedule, circulates tokens,
distributes time, and probes for new devices.
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