3. Explosion Protection Instrumentation in Zone 2/Division 2
3-20
TI 33Q01J30-01E
Parameters in Connection with FM NI Devices
Energy transfer influences FM NI properties. In order to maintain these properties, parameters
must be displayed when FM NI devices are connected.
To display parameters, FM NI devices are divided into the device that gives energy and the
device that receives energy.
Power
Supply
+
-
Lc (*1)
Cc (*2)
Li
Ci
A
B
Device that gives energy
(The source device)
Device that receives energy
(The load device)
F030115.ai
Displayed parameters
Voc: maximum open-circuit output voltage
Isc: maximum short-circuit output current
Ca: maximum allowable capacitance
La:
maximum allowable inductance
*1:
Lc: inductance of the external wiring
*2:
Cc: capacitance of the external wiring
Displayed parameters
Vmax: maximum input voltage
Imax: maximum input current
Ci:
maximum internal capacitance
Li:
maximum internal inductance
Figure Connection of FM NI Devices and Associated Parameters
How to Compare Parameters
How to compare parameters when the device that gives energy and the device that receives
energy are connected is in the following. If the parameters satisfy the following formulas, a FM
NI explosion-proof device can be connected in a general wiring. Otherwise, the wiring should
be installed to conform to NEC (National Electrical Code: ANSI/NFPA-70) or an explosion-proof
wiring defined in the relevant country.
Device that gives energy
Device that receives energy
Voc
≤
Vmax
Isc
≤
Imax
Ca
≥
summation of Ci in the device which receives
summation of capacitance Cc in the external wiring
La
≥
summation of Li in the device which receives
summation of inductance Lc in the external wiring
Dec. 3, 2021-00
