Component Variants — Series RLC Branch

The following example shows a series RLC component that implements a single resistor, inductor, or capacitor, or a series combination of these elements. The component uses conditional sections to implement the control logic.

import foundation.electrical.electrical;   % electrical domain class definition
import foundation.electrical.elements.*;   % electrical elements
component SeriesRLC
   nodes
     p = electrical; % +:left
     n = electrical; % -:right
   end
   nodes(Access=protected, ExternalAccess=none)
     rl = electrical; % internal node between r and l
     lc = electrical; % internal node between l and c
   end
   parameters
     R = {0, 'Ohm'};
     L = {0, 'H'};
     C = {inf, 'F'};
   end
   if R > 0
     components
       r = resistor(R=R);
     end
     connections
       connect(p, r.p);
       connect(r.n, rl);
     end
   else
     connections
       connect(p, rl); % short circuit p--rl
     end    
   end
   if L > 0
     components
       l = inductor(l=L);
     end
     connections
       connect(rl, l.p);
       connect(l.n, lc);
     end
   else
     connections
       connect(rl, lc); % short circuit rl--lc
     end    
   end
   if value(C, 'F') < inf
     components
       c = capacitor(c=C);
     end
     connections
       connect(lc, c.p);
       connect(c.n, n);
     end
   else
     connections
       connect(lc, n); % short circuit lc--n
     end
   end
 end

The R, L, and C parameters are initialized to 0, 0, and inf, respectively. If the block user specifies a nonzero resistance, nonzero impedance, or finite capacitance, the appropriate branch gets activated. The active branch declares the appropriate member component and connects it in series. Each of the else clauses short-circuits the appropriate nodes.

Internal nodes rl and lc, which serve to connect the member components, should not be accessible from outside the component. Set their Access attribute to protected or private. Their ExternalAccess attribute is none, so that these nodes are not visible on the block icon.