4.0 Function Blocks
4.1 Overview
The Enhanced Eclipse Model 705 Guided Wave Radar
Level Transmitter operates on the principle of Time Domain
Reflectometry (TDR). Refer to Bulletins 57-101 and 57-600
for more detailed information on the Eclipse product family.
The Enhanced Eclipse Model 705PA is a Guided Wave
Radar (GWR) level transmitter with six PROFIBUS PA
™
Blocks (one Physical Block, one Transducer Block, and four
Analog Input blocks). The idea of Function Blocks, which a
user can customize for a particular application, is a key con-
cept of fieldbus topology. Function Blocks consist of an
algorithm, inputs and outputs, and a user-defined name.
The TRANSDUCER block output is available to the net-
work through the ANALOG INPUT blocks.
The ANALOG INPUT blocks (AI) take the TRANSDUCER
block level or volume values and makes them available as an
analog value to the network. The AI blocks have scaling con-
version, filtering, and alarm functions.
The following are general descriptions of the parameters
common to all blocks. Additional information for a given
parameter is described later in that specific block section.
BLOCK_OBJECT: Contains the characteristics of the
block. This object applies to every block and is placed
before the first parameter.
ST_REV A read-only parameter to track changes of static
parameters in the associated block. ST_REV will be incre-
mented each time a static parameter is changed.
TAG_DESC (tag descriptor): A user-supplied description
of the block.
STRATEGY: A user-specified value that may be used in
configuration or diagnostics as a key in sorting block
information.
ALERT_KEY: A user-assigned value that may be used in
sorting alarms or events generated by a block.
TARGET_MODE: This attribute indicates what mode of
operation is desired for the block.
MODE_BLK: A structured parameter composed of the actual
mode, the normal and the permitted mode(s) of a block.
The actual mode is set by the block during its execution to
reflect the mode used during execution
The permitted mode shows which changes of the target
mode are valid for the specific block
20
57-645 Eclipse Guided Wave Radar Transmitter - PROFIBUS PA
™
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