Calculation Of The Maximum Cable Length; Selecting A Suitable Power Supply Device For Atex Zone Concept - E+E Elektronik EE300E Series Operating Instructions Manual

3.6

Calculation of the maximum cable length

Intrinsically safe power supply device STAHL 9160/13-11-11 (order code HA011405)
Technical data for EE300Ex
Supply voltage:
Max. current:
Technical data for STAHL 9160/13-11-11
Nominal operating voltage:
Input voltage for transmitter:
Max. load:
Calculation of maximum cable length of intrinsically safe input isolator
Cable 0.75mm²
(0.01in )
2
Load resistance (load):
Input voltage for transmitter:
Min. supply voltage EE300Ex:
Maximum voltage drop on cable:
Total cable resistance:
Transform in accordance with L
Caution: this is the max. length without allowing for the intrinsic safety.
(cable capacity and inductivity may reduce the length even further)
3.7

Selecting a suitable power supply device for ATEx zone concept:

Example for evidence of the intrinsic safety in accordance with EN60079-14:2008 12.2.5.2,
EN60079-25:2010 13.1. CH1 and CH2 are galvanically separated, meaning the evidence of the
intrinsic safety can only be carried out using appropriate equipment.
Installation assumption:
Installing the EE300Ex (without display) in Zone 0
Connecting cable length:
Explosion group:
Temperature class:
Both electric circuits laid in one cable.
Intrinsically safe power supply device STAHL 9160/13-11-11
(Excerpt from the EC type approval test certificate)
Certified to:
II 3 (1) G Ex nA nC [ia Ga] IIC T4 Gc (certificate number: DMT 03 ATEX E 010 X)
II (1) D [Ex ia Da] IIIC (certificate number: DMT 03 ATEX E 010 X)
Entity parameters:
U = 27V
0
I = 88mA
0
P = 576mW
0
C IIC = 90nF
0
C IIB = 705nF
0
L IIC = 2.3mH
0
L IIB = 17mH
0
(example):
total
300m
(984ft)
IIC
T4
20
U = 9V + RL * 0.02A
Bin
I max = 20mA
out
U = 24V
N
U = 16V
S
R = 600Ohm
L
R = 0.0267Ω/m
cable
R = 200Ω
L
U = 16V
S
U = 9V + 200Ω * 0.02A = 13V
Bmin
U = U - U = 16V – 13V = 3V
cable S Bmin
R = R * L * 2
cable total cable total
U = R * I
drop cable total out max
= R * L * 2 * I
cable total
L = U / (I * 2 * R
total drop out max
L = 3V / (0.02A * 2 * 0.0267Ω/m )
total
L = 2800m maximum cable length
total
(supply and return line)
=
out max
)
cable