Page 22 SITRANS LR250 (PROFIBUS PA) – INSTRUCTION MANUAL 7ML19985JF02
mmmmm
Wirng
The FISCO Concept allows interconnection of intrinsically safe apparatus to associated
apparatus not specifically examined in such combination. The criteria for interconnection
is that the voltage (Ui or Vmax), the current (Ii, or Imax) and the power (Pi, or Pmax) which
intrinsically safe apparatus can receive and remain intrinsically safe, considering faults,
must be equal to or greater than the voltage (Uo or Voc or Vi), the current (lo or Isc or li),
and the power (Po or Pmax) levels which can be delivered by the associated apparatus,
considering faults and applicable factors. In addition, the maximum unprotected
capacitance (Ci) and inductance (Li) of each apparatus (other than the termination)
connected to the fieldbus must be less than or equal to 5 nF and 10 µH respectively.
In each segment only one active device, normally the associated apparatus, is allowed to
provide the necessary energy for the fieldbus system. The allowed voltage Uo (or Voc or
Vt) of the associated apparatus is limited to the range of 14V dc to 24V dc. All other
equipment connected to the bus cable has to be passive, meaning that they are not
allowed to provide energy to the system, except for a leakage current of 50 µA for each
connected device. Separately powered equipment needs a galvanic isolation to assure
that the intrinsically safe fieldbus circuit remains passive.
2. Non-incendive wiring (only for USA/Canada)
• For wiring requirements: follow local regulations.
• Approved dust-tight and water-tight conduit seals are required for outdoor
NEMA 4X / type 4X / NEMA 6, IP67, IP68 locations.
• Refer to
Instructions specific to hazardous area installations
on page 23
FM/CSA Class 1, Div 2 connection drawing number 23650673
can be downloaded from the product page of our website at:
www.siemens.com/LR250
. Go to Go to More Info >
Installation Drawings > Connection Drawings.
To Next Page
Loading...
