Load &#146;Em Up!  If we know the element will respond in a
second at best, why compute a new output four times a second?
Share Print Related RSS  By John Rezabek  The Fieldbus
Foundation website, www.fieldbus.org, offers a number of free
technical documents and recommended practices. AG-181, the
Systems Engineering Guide, offers some best practices for
assigning devices to fieldbus segments, compiled in large part
from the experiences of early adopters.  Those familiar with the
origins of AG-181 know that the parts concerned with segment
loading date back to the late 90s, when devices were testing to
ITK-3 (Interoperability Test Kit-3, the mechanism by which
device suppliers prove compliance to the specs and obtain their
checkmark), and fewer than three major host suppliers were
selling an H1 interface for their core DCS offerings.  Segment
loading was based largely on loop criticality, and AG-181 puts
forward a systematic way to categorize loops on up to four
levels. The most critical loops (Level