A PI controller is to be used in a temperature control system for a bioreactor. For nominal conditions, it has been determined that the closed-loop system is stable when τ_I = 10 min and −10 < K_c < 0. Would you expect these stability limits to change for any of the following instrumentation changes? 

(a) The span on the temperature transmitter is increased from 20 ^∘C to 40 ^∘C.
(b) The zero on the temperature transmitter is decreased from 30 ^∘C to 10 ^∘C.
(c) The control valve “trim” is changed from linear to equal percentage.