The web site http://www.thevickerage.worldonline.co.uk/ecivil/comm_of_array.htm adds further information on this term as follows:
"An obsolete method of raising troops revived by King Charles during the Bishop's Wars and used again on the outbreak of the First Civil War. Commissions were sent to named gentry in every county empowering them to summon all men aged from 15 to 60 from whom fit candidates would be chosen for military training. The Commissioners of Array became the basis for Royalist county administration."