Rockwell Automation FactoryTalk View Machine Edition Users Guide - Manual (Page 496)

F ACTORY T ALK V IEW M ACHINE E DITION U SER ’ S G UIDE
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Example 2: Nested if-then-else
This expression:
if statement1 then
if statement2 then value1
else value2
else value3
has this interpretation:
Use write expressions
Write expressions allow the operator to enter a value which is manipulated by an
expression before being sent to the data source. FactoryTalk View substitutes the value the
operator enters for the placeholder in the expression, calculates the value of the
expression, and writes the result to the Value connection. All write expressions must
contain a question mark (?) as a placeholder for the value the operator enters.
You can use write expressions with the Numeric Input Enable button and the numeric
input cursor point. When the operator presses the button or cursor point, a keypad or
scratchpad opens. The operator enters a value in the keypad or scratchpad, and this value
is substituted for the ? placeholder in the write expression.