Technical Specifications

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I Integral time or reset time, is the time constant of integral con-
trol. Higher values of I cause slower integral action. A value of
zero disables integral action.
I/P Converter The electro-magnetic device which converts low energy electri-
cal current signal to a pressure which is then amplified by the
pneumatic relay.
IMan Initialization manual mode
Initialization When a downstream block is not responding to it’s setpoint an
upstream block adjusts its output so that it is at the correct
value when the downstream block returns to a mode respon-
sive to its setpoint. This provides bumpless transfer for mode
changes. See Foundation Fieldbus specifications.
Input/Output (I/O)
Subsystem Interface
This is a device used to connect other types of communications
protocols to a fieldbus Segment or Segments.
Interchangeability This is the capability to substitute a device from one manufac-
turer with that of another manufacturer on a fieldbus network
without loss of functionality or degree of integration.
Interoperability This is the capability for a device from one manufacturer to
interact with that of another manufacturer on a fieldbus network
without loss of functionality.
IRQ Interrupt Request. This is a resource that must be properly
assigned when the NIFBUS inter face card drivers are installed
in Windows.
ISA The Instrument Society of America. ISA develops and publishes
international standards for use in process control. See
www.isi.org
Link This is the logical medium by which H1 Fieldbus devices are
interconnected. It is composed of one or more physical seg-
ments interconnected by bus Repeaters or Couplers. All of the
devices on a link share a common schedule which is adminis-
tered by that link's current LAS.
Link Active Scheduler
(LAS)
A Link Active Scheduler (LAS) is a deterministic, centralized
bus scheduler that maintains a list of transmission times for all
data buffers in all devices that need to be cyclically transmitted.
Only one Link Master (LM) device on an H1 fieldbus Link can
be functioning as that link's LAS.