Rockwell Automation Safety Guidelines for the Application, Installation, and Maintenance of Solid-State Control - Manual (Page 3)

Publication SGI-1.1 - August 2009
Section 1: Definitions 3
Section 1: Definitions
Electrical Noise – Unwanted electrical energy that has the possibility of
producing undesirable effects in the control, its circuits and system.
Electrical noise includes Electromagnetic Interference (EMI) and Radio
Frequency Interference (RFI).
Electrical Noise Immunity – The extent to which the control is protected
from a stated electrical noise.
Electromagnetic Interference (EMI) – Electromagnetic disturbance that
manifests itself in performance degradation, malfunction, or failure of
electronic equipment. (IEC)
Off-State Current – The current that flows in a solid-state device in the
off-state condition.
Off-State Condition – The conditions of a solid-state device when no control
signal is applied.
On-State Condition – The condition of a solid-state device when conducting.
Radio Frequency Interference (RFI) – RFI is used interchangeably with EMI.
EMI is a later definition that includes the entire electromagnetic spectrum,
whereas RFI is more restricted to the radiofrequency band, generally
considered to be between 10k and 10G Hz. (IEC)
Surge Current – A current exceeding the steady state current for a short
time duration, normally described by its peak amplitude and time duration.
Transient Overvoltage – The peak voltage in excess of steady state voltage for
a short time during the transient conditions (e.g., resulting from the
operations of a switching device).