Manual
    <2.  Handling Cautions>
2-4
IM 01C25R03-01E
●  Installation Diagram for Nonincendive  
(Division 2 Installation)
Non-Hazardous Location
FM Approved
Associated Nonincendive Field
Wiring Apparatus
  Vt or Voc
  It or Isc
  Ca
  La
Hazardous Location
F0203.ai
Terminator
General Purpose
Equipment
Pressure
Transmitter
SUPPLY
Terminator
+
–
Transmitter
+
–
Transmitter
+
–
+ –
+ –
Note 1. Installation should be in accordance with 
the National Electrical Code ® (ANSI/NFPA 
70) Article 500.
Note 2. The conguration of Associated 
Nonincendive Field Wiring Apparatus must 
be FM Approved.
Note 3. Approved under FNICO Concept.
Note 4. Dust-tight conduit seal must be used 
when installed in Class II and Class III 
environments.
Note 5. Associated Apparatus manufacturer’s 
installation drawing must be followed when 
installing this apparatus.
Note 6. No revision to drawing without prior FM 
Approvals.
Note 7. Terminator must be FM Approved.
Note 8. The nonincendive eld wiring circuit 
concept allows interconection of 
nonincendive eld wiring apparatus with 
associated nonincendive eld wiring 
apparatus, using any of the wiring methods 
permitted for unclassied locations.
Note 9. Installation requirements; 
Vmax ≥ Voc or Vt 
Imax = see note 10. 
Ca ≥ Ci + Ccable 
La ≥ Li + Lcable
Note 10. For this current controlled circuit, the 
parameter (Imax) is not required and need 
not be aligned with parameter (Isc) of the 
barrier or associated nonincendive eld 
wiring apparatus.
Note 11. If ordinary location wiring methods are 
used, the transmitter shall be connected 
to FM Approved associated nonincendive 
eld wiring apparatus.
Electrical data:
Vmax: 32V
Ci:1.76 nF
Li: 0 µH
●  FNICO Rules
The FNICO Concept allows the interconnection of 
nonincendive eld wiring apparatus to associated 
nonincendive eld wiring apparatus not specically 
examined in such combination. The criterion for 
such interconnection is that the voltage (Vmax), 
the current (Imax) and the power (Pmax) which 
nonincendive eld wiring apparatus can receive and 
remain nonincendive, considering faults, must be 
equal or greater than the voltage (Uo, Voc or Vt), 
the current (Io, Isc or It) and the power (Po) which 
can be provided by the associated nonincendive 
eld wiring apparatus (supply unit). In addition the 
maximum unprotected residual capacitance (Ci) 
and inductance (Li) of each apparatus (other than 
terminators) connected to the Fieldbus must be less 
than or equal to 5nF and 20uH respectively.
In each N.I. Fieldbus segment only one active 
source, normally the associated nonincendive 
eld wiring apparatus, is allowed to provide the 
necessary power for the Fieldbus system. The 
allowed voltage (Uo, Voc or Vt) of the associated 
nonincendive eld wiring apparatus used to supply 
the bus cable must be limited to the range 14Vdc 
to 17.5Vdc. All other equipment connected to the 
bus cable has to be passive, meaning that the 
apparatus is not allowed to provide energy to the 
system, except a leakage current of 50 µA for each 
connected device. Separately powered equipment 
needs galvanic isolation to ensure the nonincendive 
eld wiring Fieldbus circuit remains passive.










