Rockwell Automation 1797-XXX FLEX Ex System Certification Reference Manual - Manual (Page 7)

Publication 1797-6.5.6 - June 2005
Preface 3
• U
o
= 23.7V
• I
o
= 93.5mA
In the same way, the valve is characterized by:
• C
i
= 22.5nF
• L
i
= 730
µ
H
These values are lower than what the 1797-IE8 allows:
• C
o
= 66nF
• L
o
= 2.5mH
Intrinsic Safety
Terminology The following sections describe key terms used in this reference manual:
Hazardous Area Designation
A hazardous area is designated as any location in which a combustible material
is or may be present in the atmosphere in sufficient concentration to produce
an ignitable mixture.
The North American method identifies these areas by Class, Division, and
Group while the IEC (CENELEC) designates these areas by Zone and Gas
Group.
Recently, North America has adopted the Zone method of identifying
hazardous locations as an option to the Division method.
Class Designation
Class identifies the type of hazardous atmosphere.
Class I Gas or vapor
Class II Dust
Class III Fiber or flying (no group designation)