CalcNode

An invisible widget which can perform a calculation on a set of input PVs and provides the output as a PV local to the screen.

Since different UI tools use different syntax to configure their equivalent calc tools, the calculation attribute here should be written as a general python statement. The supported operators are bitwise, negation, comparators, basic math, exponents, and boolean operations.

• Special Attributes

Name	Type	Description
pv	String	The name used to reference the output values
A	String	Input PV, the value of which can be referenced as A in the calculation
B	String	Input PV, the value of which can be referenced as B in the calculation
C	String	Input PV, the value of which can be referenced as C in the calculation
D	String	Input PV, the value of which can be referenced as D in the calculation
calc	String	The calculation to perform, provided in python syntax

• Examples

LimitCalc: !Calc
    A: "$(P)$(M).LVIO"
    B: "$(P)$(M).HLS"
    calc: "A + 2*B"
    pv: "$(P)$(M):LimitStatus"

A Calc node’s output PV can be referenced by other widgets using the visibility attribute:

BitCheck: !Calc
    A: "$(P)$(M).MSTA"
    calc: "(A & 2048) == 2048"
    pv: "$(P)$(M):HasFeature"

FeatureControls: !Group
    visibility: "$(P)$(M):HasFeature"
    children:
        - !LED { geometry: 20x20, pv: "$(P)$(M).CNEN" }