Operating instructions

20
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: U
Bin
= 9V + RL * 0.02A
Max. current: I
out
max = 20mA
Technical data for STAHL 9160/13-11-11
Nominal operating voltage: U
N
= 24V
Input voltage for transmitter: U
S
= 16V
Max. load: R
L
= 600Ohm
Calculation of maximum cable length of intrinsically safe input isolator
Cable 0.75mm²
(0.01in
2
) (example): R
cable
=0.0267Ω/m
Load resistance (load): R
L
=200Ω
Input voltage for transmitter: U
S
= 16V
Min. supply voltage EE300Ex: U
Bmin
=9V+200Ω*0.02A=13V
Maximum voltage drop on cable: U
cable
= U
S
- U
Bmin
= 16V – 13V = 3V
Total cable resistance: R
cable total
= R
cable
* L
total
* 2
(supply and return line)
U
drop
= R
cable total
* I
out max
=
= R
cable
* L
total
* 2 * I
out max
Transform in accordance with L
total
L
total
= U
drop
/ (I
out max
* 2 * R
cable
)
L
total
 =3V/(0.02A*2*0.0267Ω/m)
L
total
= 2800m maximum cable length
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: 300m
(984ft)
Explosion group: IIC
Temperature class: T4
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
0
= 27V
I
0
= 88mA
P
0
= 576mW
C
0
IIC = 90nF
C
0
IIB = 705nF
L
0
IIC = 2.3mH
L
0
IIB = 17mH