Siemens Argus 7SR21 User manual

7SR21 & 7SR22 Data Communications
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(and including any registered or unregistered design rights) are the property of Siemens Protection Devices
Limited. No part of this document shall be reproduced or modified or stored in another form, in any data retrieval
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While the information and guidance given in this document is believed to be correct, no liability shall be accepted
for any loss or damage caused by any error or omission, whether such error or omission is the result of
negligence or any other cause. Any and all such liability is disclaimed.
©2010 Siemens Protection Devices Limited
7SR21 Non-Directional
7SR22 Directional
Overcurrent Relay
Document Release History
This document is issue 2010/05. The list of revisions up to and including this issue is:
2010/05 Additional Comms modules option of (RS485 + IRIG-B) and (RS232 + IRIG-B) and typographical
revisions
2010/02 Document reformat due to rebrand
2009/09 Third Issue. Software revision 2435H80004/5 R4b-4
2008/07 Second issue. Software revision 2435H80004/5 R3d-3.
2008/03 First issue
Software Revision History
2009/09 2435H80004/5 R4b-4 CTS-I Supervision. Undercurrent 37G & 37SEF. Vx U/O Voltage.
46BC U/C. Comms Settings. Waveform Storage Settings. Fault
Storage Settings. Energy Storage. Trip test function. Local/Remote
modes. Settings ranges extended. Protocol changes.
2008/07 2435H80004/5R3d-3 Demand records. Optional DNP3.0 data comms.
2008/03 2435H80004/5R2c-2b First Release

7SR21 & 7SR22 Data Communications
Contents
Section 1: Introduction..........................................................................................................................4
Section 2: Physical Connection............................................................................................................5
2.1 Communication ports................................................................................................................5
2.1.1 Standard USB Interface...............................................................................................5
2.1.2 Standard RS485 Interface............................................................................................6
2.1.3 Optional Fibre Optic Interface......................................................................................7
2.1.4 Optional Rear RS485 + IRIG-B Interface...................................................................11
2.1.5 Optional Rear RS232 + IRIG-B Connection ..............................................................11
Section 3: Modems...............................................................................................................................12
3.1 Connecting a Modem to the Relay(s).....................................................................................12
3.2 Setting the Remote Modem....................................................................................................12
3.3 Connecting to the Remote Modem.........................................................................................12
Section 4: Configuration......................................................................................................................14
Section 5: Glossary..............................................................................................................................15
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7SR21 & 7SR22 Data Communications
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List of Figures
Figure 2-1 Communication to Front USB Port ......................................................................................6
Figure 2-2 Communication to Multiple Devices from Control System using RS485.............................6
Figure 2-3 Communication to Multiple Devices using Fibre-optic Ring Network................................10
Figure 2-4 Communication to Multiple Devices from Control System and Laptop using
Fibre-optic Star Network....................................................................................................10
Figure 2-5 Additional (Optional) Rear RS485 + IRIG-B Connection to a PC......................................11
Figure 2-6 Additional (Optional) Rear RS232 + IRIG-B Connection to a PC......................................11
Figure 2-7 RS232 Data Comms Pin Connections...............................................................................11
Figure 3-1 Communication to Device using 7SG24 and Modem........................................................13

7SR21 & 7SR22 Data Communications
Section 1: Introduction
The relay can communicate with control and automation systems, or with PCs running Reydisp Evolution
software, to provide operational information, post-fault analysis, settings, interrogation and editing facilities. This
section describes how to use the Communication Interface with a control system or interrogating computer.
Appropriate software within the control system or on the interrogating computer (e.g. Reydisp Evolution) is
required to access the interface.
This section specifies connection details and lists the events, commands and measurands provided in each
product as detailed in the Diagrams and Parameters section. For further information regarding the IEC60870-5-
103 interface, reference should be made to the separate Informative Communications Interface manual
(reference 434/TM/5 available from www.siemens.com/energy).
The Communications Interface for dialogue communications by the Protection Engineer is provided by the
Reydisp Evolution software package, also available from the website, using the IEC60870-5-103 protocol.
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7SR21 & 7SR22 Data Communications
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Section 2: Physical Connection
The relay range provides as standard one ‘Front’ USB communication interface located on the fascia and one
RS485 located at the ‘Rear’ with optional Fibre Optic ports (COM3 & COM4), RS485 (COM3) & RS232 (COM3)
also located on the rear. Communication settings are only available from the relay front fascia via the
COMMUNICATIONS MENU
1. Com2-USB: this port is used for IEC60870-5-103 (default setting) communication with the Reydisp
software. An ASCII protocol, the main use of which is to allow firmware to be updated from the front
connection, is also available through this port.
2. Com1-RS485: this port can be used for IEC60870-5-103, MODBUS RTU and DNP 3.0 communications
to a substation SCADA or integrated control system or engineer remote access.
3. Com3/Com4: Optional ports located on the rear of the relay can be used for IEC60870-5-103, MODBUS
RTU and DNP 3.0 communications to a substation SCADA or integrated control system or engineer
remote access.
Any or all ports can be mapped to the IEC60870-5-103, MODBUS RTU or DNP 3.0 protocol at any one time.
Siemens Protection Devices Limited can provide a range of interface devices, please refer to product portfolio
catalogue.
Full details of the interface devices can be found by referring to the website www.siemens.com/energy
2.1 Communication ports
2.1.1 Standard USB Interface
The USB communication port is connected using a standard USB cable with a type B connection to the relay and
type A to the PC.
The PC will require a suitable USB driver to be installed; this will be carried out automatically when the Reydisp
software is installed. When the Reydisp software is running with the USB cable connected to a device an
additional connection is shown. Connections to these devices are not shown when they are not connected.
The USB communication interface on the relay is labelled Com 2 and its associated settings are located in the
Data communications menu. To enable communication with Reydisp via the USB port the following setting
changes must be made on the relay via the keys on the relay fascia.
Setting name Range Default Setting Notes
Station Address 0 … 254 0 1-254 An address between 1 and 254
must be given to identify the
relay
COM2-USB Protocol OFF, IEC60870-5-103,
DNP3.0, MODBUS-RTU,
ASCII
IEC60870-5-
103 IEC60870-5- 103
Reydisp software uses
IEC60870-5-103 to
communicate.

7SR21 & 7SR22 Data Communications
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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 to
Include line
terminating Res
Figure 2-1 Communication to Front USB Port
2.1.2 Standard RS485 Interface
The RS485 communication port is located at the rear of the relay and can be connected using a suitable RS485
120 ohm screened twisted pair cable.
The RS485 electrical connection can be used in a single or multi-drop configuration. The RS485 master must
support and use the Auto Device Enable (ADE) feature. The last device in the connection must be terminated
correctly in accordance with the master device driving the connection. The relays are fitted with an internal
terminating resistor which can be connected between the A and B by fitting an external wire loop between
terminals 18 and 20 on the power supply module.
The maximum number of relays that can be connected to the bus is 64.
The following settings can be configured via the relay fascia or Reydisp Evolution when using the RS485
interface.
Setting name Range Default Setting Notes
Station Address
0 – 254 for IEC60870-5-103
0 – 247 for Modbus RTU
0 – 65520 for DNP3.0 0 As Required
An address within the range of the
relevant protocol must be given to
identify the relay. Each relay must
have a unique address.
COM1-RS485 Protocol OFF, IEC60870-5-103,
MODBUS-RTU, DNP3.0 IEC60870-5- 103 As Required Sets the protocol used to
communicate on the standard
RS485 connection.
COM1-RS485 Baud Rate 75 110 150 300 600 1200
2400 4800 9600 19200
38400 19200 As Required
The baud rate set on all of the
relays connected to the control
system must be the same as the
one set on the master device.
COM1-RS485 Parity NONE, ODD, EVEN EVEN As Required
The parity set on all of the relays
connected to the control system
must be the same and in
accordance with the master
device.
Unsolicited Mode DISABLED ENABLED DISABLED As Required Setting is only visible when COM1
Protocol is set to DNP3
Destination Address 0 … 65520 0 As Required Setting is only visible when COM1
Protocol is set to DNP3
Figure 2-2 Communication to Multiple Devices from Control System using RS485

7SR21 & 7SR22 Data Communications
2.1.3 Optional Fibre Optic Interface
When connecting via the optional fibre optic interface the selection of fibre-optic cable is important. Fibres must
be terminated with STTM (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 7SR21 & 7SR22 relays 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
The main factors limiting transmission distances with fibre-optics are: -
•Transmitter launch power
•Attenuation, based on light frequency, fibre material and fibre diameter
•Number of intermediate connectors and splices
•Receiver sensitivity
•The light power at the receiver must be above the sensitivity of the receiver in order that effective
communication can occur.
•Consult fibre manufacturers’ data for actual values of fibre attenuation.
•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. Consult
manufacturers’ data for actual values.
•Typical Splice losses are <0.3dB.
•A 3dB safety margin is usually allowed after the budget calculation is performed.
•Following installation the actual losses should be measured for each fibre using a calibrated light source
and meter and the measured values compared to the calculated estimate before the relay is applied.
•The fibre optic data Comms link will be broken if the relay element is withdrawn from the case.
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7SR21 & 7SR22 Data Communications
The following table can be used to record budget calculations:
A Launch power
dB
B Fibre Type
C Loss (dB/km)
dB/km
D Length
km
E Total fibre loss (CxD)
dB
F No. of Splices
G Loss at each splice
dB
H Total loss at splices (FxG)
dB
I No. of connectors
J Loss per connector
dB
K Total loss at connectors (IxJ)
dB
L Total losses (E+H+K)
dB
M Receive power budget (A-L)
dB
N Safety Margin
dB
O Device Receive Sensitivity
dB
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7SR21 & 7SR22 Data Communications
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There are two optional ports, com3 and com4, and when fitted the associated settings are available in the Data
Communication menu. To allow communication using either or both of these ports the relay settings must be
changed, via the fascia, in accordance with the method of connection and master device.
Setting name Range Default Setting Notes
Station Address
1 – 254 for IEC60870-5-103
0 – 247 for Modbus RTU
0 – 65520 for DNP3.0 0 As Required
An address within the range of
the relevant protocol must be
given to identify the relay. Each
relay must have a unique
address.
COM3 Protocol OFF, IEC60870-5-103,
MODBUS-RTU, DNP3.0 IEC60870-5- 103 As Required Sets the protocol used to
communicate on the connection
– Com3
COM3 Baud Rate 75 110 150 300 600 1200
2400 4800 9600 19200
38400 57600 115200 57600 As Required
The baud rate set on all of the
relays connected to the control
system must be the same as
the one set on the master
device.
COM3 Parity NONE, ODD, EVEN EVEN As Required
The parity set on all of the
relays connected to the control
system must be the same and
in accordance with the master
device.
COM3 Line Idle* LIGHT ON, LIGHT OFF LIGHT OFF As Required Sets the idle state of the line in
accordance with master device
COM3 Data Echo* ON,OFF OFF As Required
Set to ON when relays are
connected in a ring
configuration.
COM4 Protocol** OFF, IEC60870-5-103,
MODBUS-RTU, DNP3.0 IEC60870-5- 103 As Required Sets the protocol used to
communicate on the connection
– Com4.
COM4 Baud Rate** 75 110 150 300 600 1200
2400 4800 9600 19200
38400 57600 As Required
The baud rate set on all of the
relays connected to the control
system must be the same as
the one set on the master
device.
COM4 Parity** NONE, ODD, EVEN EVEN As Required
The parity set on all of the
relays connected to the control
system must be the same and
in accordance with the master
device.
COM4 Line Idle** LIGHT ON, LIGHT OFF LIGHT OFF As Required Sets the idle state of the line in
accordance with master device
COM4 Data Echo** ON,OFF OFF As Required
Set to ON when relays are
connected in a ring
configuration.
*Not applicable for RS 485 or RS 232 options
**COM 4 is fibre optic only

7SR21 & 7SR22 Data Communications
Figure 2-3 Communication to Multiple Devices using Fibre-optic Ring Network
Computer or
Control System
7SG24
Tx
Rx Tx
Rx
62.5/125µm fibre optic
with ST connectors
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Rx
Tx
Rx
Master
To
Control
System
USB or 9 pin male
D connector
RS232 straight
through cable
25 pin male
D connector
Figure 2-4 Communication to Multiple Devices from Control System and Laptop using Fibre-optic Star Network
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