Faudi AFGUARD - Proof of Intrinsic Safety for the Interconnection of Simple Electrical Circuitry Ex i; Installing a Measuring Point

Version 2.6
Operating instructions
AFGUARD
®
Zone 0 and Zone 1
Page: 18
of: 41
FAUDI Aviation GmbH, Scharnhorststraße 7 B, D-35260 Stadtallendorf
BA_AFGUARD_Ex_rev2.6_Englisch_l
ogo
3.3.3.2 Proof of intrinsic safety for the interconnection of simple electrical circuitry Ex i
When using AFGUARD
®
in combination with an isolating converter with transmitter supply
(sometimes together with other equipment like displays), it is evident to make sure that such
equipment may be used together. This should be done before installation. If you are not sure
on how to proceed, please contact FAUDI Aviation GmbH.
Example: Combination of AFGUARD (Ex ia IIB) together with RN 221N (E+H)
Intrinsic safe AFGUARD
Proof of intrinsic
safety
Isolating converter with
power suply
AFGUARD Zone 0/1
Ex ia IIB
RN221N (E+H)
Ex ia IIB
Data
Data
Remarks
U
i
30 V
≥
U
0
27,3
V
comply
I
i
100 mA
≥
I
0
87,6
mA
comply
P
i
750 mW
≥
P
0
597
mW
comply
L
i
+L
c
≤
L
0
18,9
mH
L
i
negligible
C
i
+C
c
≤
C
0
683
nF
C
i
negligible
cable data according to EN 60079-14, 12.2.2.2
L
C
1
µH/m
results in
18900
m
length of cable
C
C
200
pF/m
results in
3415
m
length of cable
Use the result with shorter cable length
max. cable length
3415
m
acc. EN 60079-14
The calculation delivers the maximum length of cable (please use specific cable data) to be
used for the specific combination of AFGUARD, optional Display, and isolating converter with
power supply.
3.3.4 Installing a measuring point
The AFGUARD
®
is an optical working measuring device that is designed for use in field
applications under rough conditions. Regarding these circumstances, some minimum
directives must be considered:
The optical path of the AFGUARD
®
(Glass rod, Mirror) is specially adjusted to the application.
Avoid direct contact with hard or sharp edges. Do not touch with unprotected hands.
During installation of the AFGUARD
®
, be careful when applying force.
The recommended fastening force is 50 Nm – the AFGUARD spanner should be used.
Handle the connection cable with care. Do not lay the cable under stress. Try to avoid sharp
angles.
Protect the cable against "getting caught".
Please take care of possible electrostatic charges on the outer surface of the cable. The
cable may only be cleaned by using a damp cloth.