Yokogawa FVX110 - Manual (Page 21)

<2. Handling Cautions>
2-11
IM 01S01C01-01EN
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).
Po ≤ Pi, Uo ≤ Ui, Io ≤ Ii
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.
Ci ≤ 5 nF, Li ≤ 10 µH
Supply unit
The supply unit must be certified by a Notified
body as FISCO model and following trapezoidal or
rectangular output characteristic is used.
Uo = 14...17.5 V (I.S. maximum value)
Io based on spark test result or other assessment,
No specification of Lo and Co is required on the
certificate or label.
Cable
The cable used to interconnect the devices needs
to comply with the following parameters:
Loop resistance Rc: 15...150 Ω/km
Inductance per unit length Lc: 0.4...1 mH/km
Capacitance per unit length Cc: 45...200 nF/km
Length of spur cable: max. 60 m (IIC and IIB)
Length of trunk cable: max. 1 km (IIC) or 5 km
(IIB)
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 . . . 102 Ω
C = 0 . . . 2.2 µF. (0.8...1.2 µF is required in
operation)
The resistor must be infallible according to IEC
60079-11.
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
F0210.ai
Terminator
Ex i
Field Instruments
(Passive)
Hand-
held-
Terminal
Supply Unit and
Safety Barrier
Terminator
Data
U
U
I
I.S. fieldbus system complying with Entity model
I.S. values Power supply-field device:
Po ≤ Pi, Uo ≤ Ui, Io ≤ Ii
Calculation of max. allowed cable length:
Ccable ≤ Co – ∑Ci – ∑Ci (Terminator)
Lcable ≤ Lo – ∑Li
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.
b. CENELEC ATEX (KEMA) Flameproof Type
Caution for CENELEC ATEX (KEMA)
flameproof type
Note 1. FVX110 Fieldbus Segment Indicator
with optional code /KF25 for potentially
explosive atmospheres:
• No. KEMA 10ATEX0157
• Applicable Standard:
EN 60079-0:2006, EN 60079-1:2004,
EN 61241-0:2006, EN 61241-1:2004
• Type of Protection and Marking Code:
Ex d IIC T6, Ex tD A21 IP6x T80
• Group: II
• Category: 2G, 2D
• Temperature Class: T6
• Enclosure: IP66 and IP67
• Ambient Temperature for gas-proof:
–50* to 75ºC (T6)
* –15ºC when O-ring material is Fluoro-rubber.
• Maximum Surface Temperature for dust-
proof:
T80ºC (Tamb.: –40* to 75ºC)
* –15ºC when O-ring material is Fluoro-rubber.