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SERIES 3000 MKII TECHNICAL MANUAL
S3KMKIIMAN_MAN0878_Issue 6_01/2014
6.1 Detector wiring schematic
Caution: All electrical connections should be made in accordance with any
relevant local or national legislation, standards or codes of practice.
6.2 Typical maximum installed cable lengths
The formula for calculating the maximum installed cable length between a controller and detector D
(meters) is given below.
D = ( ( ( Vc - Vdmin - ( Im * RL ) ) / ( 2 * Im * Rc ) ) ) * 1000
Notes:
• Distance km=kilometres, mi=miles.
• Assuming Vc=24Vdc, Vdmin=17Vdc, Im=22mA
For the value of RC, use the data supplied by the manufacturer of the cable to be used for the
specific installation.
V
c
V
d
I
m
R
c
V
c
V
d
I
m
R
c
V
c
V
d
I
m
R
c
Diagram 7: Wiring Schematic Type 1
Controller
1
2
+VE
1
2
Detector
+VE
-VE
R
L
Signal
-VE
V
c
V
d
R
c
I
m
Controller
1
2
+VE
1
2
Detector
+VE
-VE
R
L
Signal
-VE
V
c
V
d
R
c
I
m
Diagram 8: Wiring Schematic Type 2
Detector Supply V
d
•
17Vdc (+/-10%) < V
d
< 32Vdc (max)
Maximum Detector Signal I
m
•
I
m
= 22mA (over range)
Cable Resistance R
c
•
Subject to cable type
•
Typical values are:
0.5mm
2
(20AWG*) = 36.8
Ω
/km (59.2
Ω
/mi)
1.0mm
2
(17AWG*) = 19.5
Ω
/km (31.4
Ω
/mi)
1.5mm
2
(16AWG*) = 12.7
Ω
/km (20.4
Ω
/mi)
2.0mm
2
(14AWG*) = 10.1
Ω
/km (16.3
Ω
/mi)
*nearest equivalent
Load Resistor of Control Panel R
L
•
Assumed 33
Ω
(min) / 250
Ω
(max)
Controller Supply Voltage V
c
•
Subject to controller manufacturer
•
Assumed nominal of 24Vdc
Typical cable data
Cable distance km (mi)
Cable size
Cable resistance
Rc Ω/km (Ω/mi)
Example 1 Input
impedance RL = 33Ω
Example 2 Input
impedance RL = 250Ω
0.5mm2 (20AWG*)
36.8 (59.2)
3.9 (2.4)
0.9 (0.6)
1.0mm2 (17AWG*)
19.5 (31.4)
7.3 (4.5)
1.7 (1.1)
1.5mm2 (16AWG*)
12.7 (20.4)
11.2 (7.0)
2.7 (1.7)
2.0mm2 (14AWG*)
10.1 (16.3)
14.1 (8.8)
3.4 (2.1)
*Nearest equivalent
