Outputting EMTDC Measured Voltages and Currents
An Internal Output Variable is internal component data, which has been made available as a signal to be plotted or monitored. Any internal quantities that need to be to be output must either be passed through an output parameter, or be defined within the component Fortran segment using an #OUTPUT directive.
Internal data used as output can either come from an internal component variable, from an EMTDC storage array, or as a measured branch current or voltage from EMTDC.
There are a couple of substitution operators that can be used with #OUTPUT directives to extract measured quantities directly from electrical system nodes and branches. These are described below.
CBR is a special substitution operator that will output the current measured in a specified branch. A special syntax is used for this – see the example below.
EXAMPLE 9-12:
A user wants to measure the current in a branch called BRN. A text field has been added to the component Parameters section with Symbol name Ia.
The following should then appear in the Fortran segment:
#OUTPUT REAL Ia {$CBR:BRN}
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VDC is a special substitution operator that will take the voltage difference between two different electrical nodes. A special syntax is used for this – see the example below.
EXAMPLE 9-13:
A user wants to measure the voltage difference between two port connections defined within a component definition, called N1 and N2. A text field has been added to the component Parameters section with symbol name Vdiff.
The following should then appear in the Fortran segment:
#OUTPUT REAL Vdiff {$VDC:N1:N2}
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NOTE: It is important to ensure that neither N1 nor N2 are type ground nodes. The reason being is that ground nodes are given a 0 node number, which is an invalid entry to the VDC(NA,SS) array.