Yokogawa YVP110 User Manual
Page 19
<1. Notes on Handling>
1-8
IM 21B04C01-01E
FISCO Model
Non-hazardous
Locations
Hazardous Locations
F0106.ai
Terminator
(FISCO Model)
Ex i
Field Instruments
(Passive)
Hand-
held-
Terminal
Supply Unit
(FISCO Model)
Terminator
Data
U
U
I
I.S. fieldbus system complying with FISCO
The criterion for such interconnection is that the
voltage (Ui), the current (Ii) and the power (Pi),
which intrinsically safe apparatus can receive,
must be equal or greater than the voltage (Uo),
the current (Io) and the power (Po) which can be
provided by the associated apparatus (supply unit).
In addition, the maximum unprotected residual
capacitance (Ci) and inductance (Li) of each
apparatus (other than the terminators) connected
to the fieldbus line must be equal or less than 5 nF
and 10 µH respectively.
Supply unit
The supply unit must be certified by a notified body
as FISCO model and following trapezoidal output
characteristic is used.
Uo = 14 to 24 V (I.S. maximum value)
Io based on spark test result or other assessment,
ex. 133 mA for Uo = 15 V (Group IIC)
The maximum allowed Co and Lo are determined
by the combinations as specified below.
Cable
The cable used to interconnect the devices needs
to comply with the following parameters:
loop resistance R': 15 to 150 Ω/km
inductance per unit length L': 0.4 to 1 mH/km
capacitance per unit length C': 80 to 200 nF/km
C' = C' line/line + 0.5 C' line/screen, if both lines
are floating
or
C' = C' line/line + C' line/screen, if the screen is
connected to one line
length of spur cable: max. 30 m (Ex ia IIC T4) or
120 m (Ex ia IIB T4)
length of trunk cable: max. 1 km (Ex ia IIC T4)
or 1.9 km (Ex ia IIB T4)
Terminators
The terminator must be certified by a notified body
as FISCO model and at each end of the trunk
cable an approved line terminator with the following
parameters is suitable:
R = 90 to 100 Ω
C = 0 to 2.2 µF
The resistor must be infallible according to EN
50020. One of the two allowed terminators might
already be integrated in the associated apparatus
(bus supply unit).
Number of Devices
The number of devices (max. 32) possible on a
fieldbus link depends on factors such as the power
consumption of each device, the type of cable used,
use of repeaters, etc.
Entity Model
Non-hazardous
Locations
Hazardous Locations
F0107.ai
Terminator
Ex i
Field Instruments
(Passive)
Hand-
held-
Terminal
Supply Unit
Terminator
Data
U
U
I
I.S. fieldbus system complying with Entity model