The Economatics Control ROM was written to control models built with the fischertechnik Computing Experimental kit on BBC computers (B, B+, and Master, but not the Master Compact). The physical control interface was (I think) the fischertechnik Acorn Interface, which is probably more or less unobtainable now.
The ROM might be used nowadays for the turtle graphics package that it contains, or possibly the integer trigonometry routines *Sin and *Cos
Yes, I know, I know! I was made to do it, OK? :-)