Model is underconstrained.
The following variables couldn't be defined:
 * EH in component EH
 * d/dt EH in component EH
 * d/dt E in component E
 * d/dt EH2 in component EH2
 * d/dt EH_ in component EH_
 * d/dt E_ in component E_
 * d/dt EH2_ in component EH2_