Specifications

Glossary
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N
N.C. contact
normally closed contact. A relay contact pair that is closed when the relay coil is de-
energized and open when the coil is energized.
N.O. contact
normally open contact. A relay contact pair that is open when the relay coil is de-
energized and closed when the coil is energized.
NEMA
National Electrical Manufacturers Association
network cycle time
The time that a master requires to complete a single scan of all of the configured I/O
modules on a network device; typically expressed in microseconds.
NIM
network interface module. This module is the interface between an Island bus and
the fieldbus network of which the Island is a part. A NIM enables all the I/O on the
Island to be treated as a single node on the fieldbus. The NIM also provides 5 V of
logic power to the Advantys STB I/O modules in the same segment as the NIM.
NMT
network management. NMT protocols provide services for network initialization,
diagnostic control, and device status control.
O
object dictionary
Part of the CANopen device model that provides a map to the internal structure of
CANopen devices (according to CANopen profile DS-401). A device’s object
dictionary (also called the object directory) is a lookup table that describes the data
types, communications objects, and application objects the device uses. By
accessing a particular device’s object dictionary through the CANopen fieldbus, you
can predict its network behavior and build a distributed application.