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2 expression block (ex) – Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) Algorithms, Tables and Sequential Logic Functions User Manual

Page 11

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Logic Functions - Book 2

EXPRESSION BLOCK

8-3

8.2

EXPRESSION BLOCK (EX)

The expression block evaluates a user-specified expression each time it executes. Logical,
arithmetic, and conditional operators can be mixed at will in the expression, with the final
result being scaled to a configured data type. An auxiliary output can provide the result scaled
to another data type. Expressions are entered by the user in algebraic format using ‘C’
symbology for operators and functions and assuming ‘C’ like operator precedence. An
expression can be as simple as a single operand (result data type must be configured in this
case) or as complex as can be fit on the configurator screen.

Block outputs are the result, auxiliary result, and their qualities. A functional block diagram of
an expression block is shown in Figure 8-1. The displays, which are used to configure the
Expression block, are shown in Figure 8-2 (page 1), Figure 8-3 (page 2) and Figure 8-4 (page
4).

Syntax Error

Calculation Error

Result

RQ

Input (1) Status

Input No. 1

Bad Inputs

Accepted

(YES/NO)

BAD

GOOD

Quality Check

State

(RUN, HOLD,

OFF, DEBUG)

Expression

Evaluation

Calculation Error

(ENABLE/

SUPPRESS)

Input No. 46

Expression

Error

AUXQ

Auxiliary

Result

Input (46) Status

BAD

GOOD

Data Type

Conversion

Data Type

Conversion

Set Quality BAD

on Calculation

Error?

(YES/NO)

Diagnostic

Group

(NONE, 1 - 7)

CERRAQ

CERRA

CERRUQ

CERRU

ETYPE

EPOS

Figure 8-1. Functional Block Diagram, Expression Block