2 expression block (ex) – Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) Algorithms, Tables and Sequential Logic Functions User Manual
Page 11

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