Linear Multi-Input - Multi-Output (MIMO) transfer function models are
obtained for various distillation control schemes from the transfer fu
nction model of [L, V] control structure using the transformation meth
od of HAGGBLOM and WALLER [3]. The requirements to be met by the base
[L, V] control structure model are examined in two examples. Second-or
der lag approximations for the transfer functions between the composit
ions and the primary manipulative variables (G(yu)(LV)) are used. Prop
ortional plus first-order lag approximations for the transfer function
s between the primary and the inventory manipulative variables (G(yu)(
LV)) are found to be acceptable.