Communication Basics

The Communication section within an SCL file allows for the specification of the network, its access points, and the configuration of each access point.

It includes at least one SubNetwork as its child element, which can be configured through the child element BitRate. Each SubNetwork can have multiple ConnectedAP elements, which serve as pointers to IEDs AccessPoints, defined by attributes iedName and apName. Each ConnectedAP id associated with one Address element, and within it, there are P elements corresponding to the settings for that particular access point.

A P element is structured as follows:

<P type="IP">192.168.210.122</P>

Here, the type attribute defines the setting type, and the inner text (here 192.168.210.122) of the element defines the setting value. OpenSCD supports various other optional setting types for configuration:

• IP
• IP-SUBNET
• IP-GATEWAY
• OSI-TSEL
• OSI-SSEL
• OSI-PSEL
• OSI-AP-Title
• OSI-AP-Invoke
• OSI-AE-Qualifier
• OSI-AE-Invoke
• OSI-NSAP
• VLAN-ID
• VLAN-PRIORITY
• SNTP-Port
• MMS-Port
• DNSName
• UDP-Port
• TCP-Port
• C37-118-IP-Port
• IPv6
• IPv6-SUBNET
• IPv6-GATEWAY
• IPv6FlowLabel
• IPv6ClassOfTraffic
• IPv6-IGMPv3Src
• IP-IGMPv3Sr
• IP-ClassOfTraffic

Each is backed up with pattern check against the pattern defined in the schema (2007B4).

A very typical Communication section might look like this:

<SubNetwork type="8-MMS" name="Stationbus" desc="Subnetwork">
    <BitRate unit="b/s" multiplier="M">10</BitRate>
    <ConnectedAP iedName="AA1E1Q04MU" apName="AP1">
        <Address>
            <P type="IP">192.168.210.142</P>
            <P type="IP-SUBNET">255.255.255.0</P>
            <P type="IP-GATEWAY">192.168.210.1</P>
            <P type="OSI-PSEL">00000001</P>
            <P type="OSI-SSEL">0001</P>
            <P type="OSI-TSEL">0001</P>
            <P type="OSI-AP-Title">1,3,9999,23</P>
            <P type="OSI-AE-Qualifier">23</P>
        </Address>
    </ConnectedAP>
    <ConnectedAP iedName="AA1E1Q02BCU" apName="AP1" redProt="prp">
        <Address>
            <P type="IP">192.168.210.121</P>
            <P type="IP-SUBNET">255.255.255.0</P>
            <P type="IP-GATEWAY">192.168.210.1</P>
            <P type="OSI-PSEL">00000001</P>
            <P type="OSI-SSEL">0001</P>
            <P type="OSI-TSEL">0001</P>
            <P type="OSI-AP-Title">1,3,9999,23</P>
            <P type="OSI-AE-Qualifier">23</P>
        </Address>
    </ConnectedAP>
</SubNetwork>

NOTE: in addition to the namespace xmlns="http://www.iec.ch/61850/2003/SCL" SCL files can also include xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance". This inclusion facilitates faster parsing of an SCL file for communication type configuration. An example of a P type element is provided below:

<P xsi:type="tP_IP" type="IP">192.168.210.122</P>