Q

quadrature

The separation in phase by 90 degrees. It is used on signal channels of feedback devices such as encoders and resolvers to detect the direction of motion.

quality of data

Quality of data is implemented using the

Valid

attribute on sequencing parameters and step tags. Sequencing output parameters and step output tags can be configured to have valid or invalid values when the sequence is initialized. The

Valid

attribute is set TRUE when a value is stored into the tag: when the sequence is initialized, when the tag’s expression evaluates, when a phase request stores a value into a step output tag, or when an operator assigns a value.

Quality of data impacts the evaluation of parameter expressions. When any term in an expression references a sequencing parameter or step tag with an invalid value, the tag’s

Value

attribute is assigned the result of the expression and the

Valid

attribute is set FALSE.

Quality of data impacts the evaluation of transition expressions. When any term in the transition expression references a sequencing parameter or step tag with an invalid value, the transition expression evaluates FALSE.