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MessengerBLE
User Guide
9.18
EVAL Expression Configuration – Type 10
An expression can be used to calculate a value from inputs/outputs in the system. Some
examples would be to scale a value, do units conversion on a value, compute a logical
value for activating an output, detecting an alarm, etc. Expressions are user entered and
can contain up to 4 operands, A, B, C, and D.
Parameters for Expression Configuration
Parameter
Code
Reference Description
Default
1
Name
A representative name to reference the
expression by.
C
ASCII Text
30 characters max
2
Enable
Defines whether or not this expression
will be evaluated
0
0 = disabled
1 = enabled
3
Evaluation
Order
There are 2 levels of expression
evaluation. Level 2 is only necessary if
an intermediate value must first be
calculated.
8
1 = evaluate first
2 = evaluate second
4
Evaluation
Type
Defines the expected data type of the
result.
1
0 – none
1 – logic (digital)
2 – numeric (no decimal)
3 – float (arithmetic)
5
Expression User entered expression
1
Examples:
a+b
a+b-c
a*b
a*b/c
a && b
a || b
a > b
Operand A
10
Type
Operand A type
1
0 = none
1 = variable
2= constant