Reference Manual

2−11
Actuator Selection Summary
D Actuator selection must be based upon a
balance of process requirements, valve
requirements and cost.
D Simple designs such as the spring-and-
diaphragm are simpler, less expensive and easier
to maintain. Consider them first in most situations.
D Piston actuators offer many of the
advantages of pneumatic actuators with higher
thrust capability than spring-and-diaphragm styles.
They are especially useful where compactness is
desired or long travel is required.
D Electric and electro-hydraulic actuators
provide excellent performance. They are, however,
much more complex and difficult to maintain.
D Actuator sizing is not difficult, but the wide
variety of actuators and valves make it difficult to
master. Vendor expertise is widely available.
D Systems such as control valves are best
purchased, assembled and tested by one source.
Figure 2-9. The FIELDVUE Digital Valve Controller
brings increased control accuracy and flexibility.
When utilized with AMS ValveLinkt software,
FIELDVUE instruments provide valuable diagnostic
data that helps to avoid maintenance problems.
W9915
Use of actuators and accessories of the same
manufacturer will eliminate many problems.