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Data quality, Logical source pointer (lsp) – Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) System, I/O and Communications Functions User Manual

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Logic Functions - Book 1

DATABASE DESCRIPTION

2-5

block is executed. However, if the input mode is configured to be manual, the initial data
value will be retained until it is written over by an operator through the status display, or until
input mode is changed to auto. If an input attribute is configured as NONE, then that attribute
is not part of the database and cannot be read.

2.3.2

Data Quality

Each block with a calculated output carries a quality attribute in the database directly following
any attribute which is calculated by the block algorithm (block outputs). Attributes which can
only be configured, changed by the operator, or obtained through source pointers do not carry
quality.

Most blocks deal with quality in a standard way. There is a "Bad Inputs Accepted" parameter
in every function block. When this attribute is set to YES, the block will not check quality on its
inputs and will not change the quality of its outputs; quality of outputs in this case will default to
GOOD. When the "Bad Inputs Accepted" parameter set to NO, the block will check all of its
inputs for quality prior to executing its algorithm. If any of those which have quality are found
’not good’, the block will not execute its algorithm but will mark its output quality(s) bad,
leaving output data at its previous value.

Individual blocks may deal with data quality in a more specific manner, by offering separate
checks and "actions on bad quality" for individual inputs or groups of inputs, and by offering
different actions on different grades of quality.

Quality information is provided to the operator either by pointing an alarm block at the desired
quality attribute or by making quality one of the conditions you can alarm on when you point
an alarm block at a variable.

2.3.3

Logical Source Pointer (LSP)

Information is passed between blocks in the database by means of software sources. Input
information is provided via software links (softwiring) to all function block characteristics, with
the exception of discrete input and analog input type blocks, which read data from their
process connections. Softwiring between database memory blocks allows complex
interconnections of raw and processed signals within and between instrument databases.

The current state or condition of any block is accessible to all other function blocks by
softwiring to the data in the block using the respective mnemonics. When other information in
a block is required, this too can be obtained by softwiring to the respective characteristic.
Softwiring is accomplished through the use of source codes. A logical source pointer (LSP) is
used to specify a field in one block as the data source for a field in another block. The LSP
code specifies the block type and occurrence number of the database block acting as the
source and the mnemonic for the field in the block (e.g. EX2,R is a LSP that identifies
Expression Block No. 2, Result Field). This LSP must be entered in a field of the block that is
receiving the data (the destination block).

As data in a function block is only referred to, and not physically used (as if it were similar to a
relay contact), there is no restriction to the amount of times or position in the logic
arrangement that reference is made, e. g., any LSP can be the source of data for as many
function block fields as necessary.