7SR242 Duobias Technical Manual
Chapter 4 - Page 10 of 92
© 2015 Siemens Protection Devices Limited
To Control
System
14
16
18
20
RS485 Screened
twisted pair
Rear terminals
14
16
18
14
16
18
RS485 Screened
twisted pair
Rear terminals
Ext Wire loop
(terminating
resistance) added
where permanent
drive from master
station available
A
RS485
G
N
D
B
T
e
rm
.
1
4
1
6
1
8
2
0
A
RS485
G
N
D
B
T
e
rm
.
1
4
1
6
1
8
2
0
A
RS485
G
N
D
B
T
e
rm
.
1
4
1
6
1
8
2
0
RS 485 Twisted pair Cable
To Control
System
Bus Termination Polarity
5V
B
A
GND
Fig. 2-2 Communication to Multiple Devices using RS485 (Standard Port)
2.4 Serial Fibre Optic Interface (COM3 & COM4)
When connecting via the optional fibre optic interface the selection of fibre-optic cable is important. Fibres must be
terminated with ST™ (BFOC/2.5) connectors.
The recommended type is 62.5/125µm glass fibre. Communication distances over 1 km are achievable using this
type of fibre.
A budget loss calculation should be made for all installations. The following table gives the launch power and receiver
sensitivity of each of the fibre optic communication ports on the Relay when used with specific fibre optic types.
Tx Launch Power (dB)
RX Receive Sensitivity (dB)
Fibre Type
Min
Max
Min
Max
62.5/125µm
-11.7
-15.7
-24
-9.2
1mm Polymer
-6.4
-10.4
-24
-9.2
200µm PCS
-2.8
-6.8
-24
-9.2
Factors to be considered when calculating fibre-optic transmission distances:
•
Transmitter launch power.
•
Attenuation, based on light frequency, fibre material and fibre diameter. (Consult fibre
manufacturers' data for actual values of fibre attenuation).
•
Number of intermediate connectors and splices. Fibre cables are supplied on reels of
finite length which may necessitate additional jointing. Typical losses at connectors are
0.5-1.0dB each. This allows for normal age related deterioration. Typical losses at splices
are <0.3dB. (Consult fibre manufacturers' data for actual values).
Summary of Contents for 7SR242 Duobias
Page 1: ...Answers for energy 7SR242 Duobias Transformer Protection Relay Reyrolle Protection Devices ...
Page 2: ...2 ...
Page 4: ...4 ...
Page 6: ...6 www siemens com energy ...
Page 318: ... 2015 Siemens Protection Devices Limited Chapter 7 Page 2 of 64 ...
Page 324: ... 2015 Siemens Protection Devices Limited Chapter 7 Page 8 of 64 ...
Page 358: ... 2015 Siemens Protection Devices Limited Chapter 7 Page 42 of 64 ...
Page 366: ... 2015 Siemens Protection Devices Limited Chapter 7 Page 50 of 64 ...
Page 380: ... 2015 Siemens Protection Devices Limited Chapter 7 Page 64 of 64 ...
Page 381: ......