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Pivot object model

The pivot object model is based on 61850 semantic.

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• if CA of ASDU is known otherwise throw an error message.
• if IOA is known otherwise throw an error message.
• if type of ASDU is known otherwise an error message.
• The label attribute shall be used to populate the Fledge's DataPoint Asset Name attribute.

Attributes definition

Configuration JSON structure

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{
   "protocol_stack":{
      "name":"iec104client",
      "version":"1.0",
      "transport_layer":{
         "connectionredundancy_groups":[
            {
               "pathconnections":[
                  {
                     "srv_ip":"192.168.0.10",
                     "clt_ip":"",
port":2404,
                     "conn":true,
                     "portstart":2404true
                  },
                  {
                     "srv_ip":"192.168.0.11",
                     "clt_ipport":""2404,
                     "portconn":2404true,
               }
      "start":false
      ],
            "tls":false}
         },
      ],
      "k_value":12,
         "wrg_valuename":8"red-group-1",
               "t0_timeouttls":10,false
          "t1_timeout":15  },
         "t2_timeout":10,
   {
      "t3_timeout":20,
         "conn_allconnections":true,[
         "start_all":false,
         "conn_passv":false{
      },
      "application_layer":{
         "origsrv_addrip":"192.168.0.12",
         "ca_asdu_size":2,
            "ioaddr_sizeport":32404,
            "startup_time":180,
         "asdu_sizeconn":0false,
         "gi_time":60,
            "gi_cyclestart":false,
         "gi_all_ca":false,
         "gi_repeat_count":2},
         "disc_qual":"NT",
         "send_iv_time":0,{
         "tsiv":"REMOVE",
            "utcsrv_time":false,
ip":"192.168.0.13",
                     "comm_wttagport":false2404,
         "comm_parallel":0,
            "exec_cycl_testconn":false,
            "startup_state":true,
         "reversestart":false,
         "time_sync":false
      }
   }
}

IEC 104 datapoint representation

This is the Datapoint representation of an IEC 104 ASDU.

{
   "data_object":{
      "do_type":"type_id",
      "do_ca":"ca",
],
               "dorg_oaname":"oared-group-2",
               "do_cottls":"cot",false
      "do_test":"istest",
      "do_negative":"isnegative",}
      "do_ioa":"ioa"   ],
         "dok_value":"value"12,
         "dow_qualityvalue":"quality_desc"8,
         "dot0_tstimeout":"time_marker"10,
         "do_ts_qual":"isinvalid",
t1_timeout":15,
         "t2_timeout":10,
         "t3_timeout":20,
         "do_ts_sum_time":"isSummerTime"
   }
}

Path exploration

In redundant network configuration or generally in cases where several communication paths exist between one client and one server, the path checking exploration mechanism allows the client to try all the paths one by one without making any difference between them. The client uses the first available path. On disconnection this procedure starts again from the beginning.

TLS configuration

The CS 104 standard can also be used with TLS to realize secure and authenticated connections.

3 parameters are needed to set up the TLS secured connection:

• private key file
• server certificate
• root certificate (CA)

Fledge's certificate store allows certificates to be stored and used by the south plugins.

{
  "tls_conf:": {
    "private_key": "server-key.pem",
    "server_cert": "server.cer",
    "ca_cert": "root.cer"
  }
}

IEC 104 north plugin (server/slave)

IEC 104 redundancy server modes

Multiple redundancy groups

The MZ Automation lib60870 server provides 3 different modes regarding the support of redundant connections and events queue handling:

• The default mode (CS104_MODE_SINGLE_REDUNDANCY_GROUP) allows only a single active client connection.
• The second mode (CS104_MODE_CONNECTION_IS_REDUNDANCY_GROUP) allows multiple active client connections.
• The third mode (CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS) allows multiple active client connections while preserving events when no client is connected.

In the case of this design, the south plugin will be implemented with CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS server mode.

This mode allows multiple active client connections while preserving events when no client is connected. In this mode clients can be assigned to specific redundancy groups. The assignment is based on the IP address of the client. A redundancy group can have multiple simultaneous connections but only one of these connections can be active. The number of activated connections is restricted by the number of redundancy groups. Each redundancy group has a dedicated event queue.

It can be set with the CS104_Slave_setServerMode function:

CS104_Slave_setServerMode(slave, CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS);

Multiple redundancy groups example

conn_all":true,
         "start_all":false,
         "conn_passv":false
      },
      "application_layer":{
         "orig_addr":0,
         "ca_asdu_size":2,
         "ioaddr_size":3,
         "startup_time":180,
         "asdu_size":0,
         "gi_time":60,
         "gi_cycle":false,
         "gi_all_ca":false,
         "gi_repeat_count":2,
         "disc_qual":"NT",
         "send_iv_time":0,
         "tsiv":"REMOVE",
         "utc_time":false,
         "comm_wttag":false,
         "comm_parallel":0,
         "exec_cycl_test":false,
         "startup_state":true,
         "reverse":false,
         "time_sync":false
      }
   }
}

IEC 104 datapoint representation

This is the Datapoint representation of an IEC 104 ASDU.

{
   "data_object":{
      "do_type":"type_id",
      "do_ca":"ca",
      "do_oa":"oa",
      "do_cot":"cot",
      "do_test":"istest",
      "do_negative":"isnegative",
      "do_ioa":"ioa",
      "do_value":"value",
      "do_quality":"quality_desc",
      "do_ts":"time_marker",
      "do_ts_qual":"isinvalid",
      "do_ts_sum_time":"isSummerTime"
   }
}

Path exploration

In this example, 2 control centers, center A and B, are establishing communication with the server.

Both centers have an active and a stand-by gateway for failover management. 

Center A has two simultaneous connections, one active and one stand-by, assigned to redundancy group 1.

Center B has only one active connection, assigned to redundancy group 2.

IEC 104 Protocol stack configuration

The IEC 104 protocol stack configuration specifies communication parameters and is a collection of entries containing information about OSI Transport and OSI Application layers objects.

Each entry is comprised of attributes that describe the object. All the configuration data are structured using JSON.

Each entry shall be mapped with the corresponding configuration function in the chosen implementation protocol library.

Attributes definition

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maximum ASDU size in transmission direction, if set to "0" => maximum possible value is automatically used.

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ignore, process, default = ignore

ignore: the time stamp quality 'not synchronized' will be ignored and the time stamp will be processed on regular basis. IV-bit will remain 0

process: the time stamp will be send with IV-bit set to 1

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redundant network configuration or generally in cases where several communication paths exist between one client and one server, the path checking exploration mechanism allows the client to try all the paths one by one without making any difference between them. The client uses the first available path. On disconnection this procedure starts again from the beginning.

TLS configuration

The CS 104 standard can also be used with TLS to realize secure and authenticated connections.

3 parameters are needed to set up the TLS secured connection:

• private key file
• server certificate
• root certificate (CA)

Fledge's certificate store allows certificates to be stored and used by the south plugins.

{
  "tls_conf:": {
    "private_key": "server-key.pem",
    "server_cert": "server.cer",
    "ca_cert": "root.cer"
  }
}

IEC 104 north plugin (server/slave)

IEC 104 redundancy server modes

Multiple redundancy groups

The MZ Automation lib60870 server provides 3 different modes regarding the support of redundant connections and events queue handling:

• The default mode (CS104_MODE_SINGLE_REDUNDANCY_GROUP) allows only a single active client connection.
• The second mode (CS104_MODE_CONNECTION_IS_REDUNDANCY_GROUP) allows multiple active client connections.
• The third mode (CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS) allows multiple active client connections while preserving events when no client is connected.

In the case of this design, the south plugin will be implemented with CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS server mode.

This mode allows multiple active client connections while preserving events when no client is connected. In this mode clients can be assigned to specific redundancy groups. The assignment is based on the IP address of the client. A redundancy group can have multiple simultaneous connections but only one of these connections can be active. The number of activated connections is restricted by the number of redundancy groups. Each redundancy group has a dedicated event queue.

It can be set with the CS104_Slave_setServerMode function:

CS104_Slave_setServerMode(slave, CS104_MODE_MULTIPLE_REDUNDANCY_GROUPS);

Multiple redundancy groups example

In this example, 2 control centers, center A and B, are establishing communication with the server.

Both centers have an active and a stand-by gateway for failover management. 

Center A has two simultaneous connections, one active and one stand-by, assigned to redundancy group 1.

Center B has only one active connection, assigned to redundancy group 2.

IEC 104 Protocol stack configuration

The IEC 104 protocol stack configuration specifies communication parameters and is a collection of entries containing information about OSI Transport and OSI Application layers objects.

Each entry is comprised of attributes that describe the object. All the configuration data are structured using JSON.

Each entry shall be mapped with the corresponding configuration function in the chosen implementation protocol library.

Attributes definition

Configuration JSON structure

{
   "protocol_stack":{
      "name":"iec104server",
      "version":"1.0",
      "transport_layer":{
         "redundancy_groups":[
            {
               "connections":[
                  {
                     "clt_ip":"192.168.0.10",
                     "port":2403
                  },
                  {
                     "clt_ip":"192.168.0.11",
                     "port":2404
                  },
                  {
                     "clt_ip":"10.152.1.10",
                     "port":2405
                  },
                  {
                     "clt_ip":"10.152.1.11",
                     "port":2406
                  }
               ],
			   "rg_name":"red-group-1",
               "tls":false,
               "k_value":12,
               "w_value":8,
               "t0_timeout":10,
               "t1_timeout":15,
               "t2_timeout":10,
               "t3_timeout":20
            },
            {
               "connections":[
                  {
                     "clt_ip":"192.168.0.10",
                     "port":2403
                  },
                  {
                     "clt_ip":"192.168.0.11",
                     "port":2404
                  },
                  {
                     "clt_ip":"192.168.0.12",
                     "port":2405
                  },
                  {
                     "clt_ip":"192.168.0.14",
                     "port":2406
                  },
                  {
                     "clt_ip":"10.152.1.10",
                     "port":2403
                  },
                  {
                     "clt_ip":"10.152.1.11",
                     "port":2404
                  },
                  {
                     "clt_ip":"10.152.1.12",
                     "port":2405
                  },
                  {
                     "clt_ip":"10.152.1.13",
                     "port":2406
                  }
               ],
			   "rg_name":"red-group-2",
               "tls":false,
               "k_value":12,
               "w_value":8,

...

Configuration JSON structure

{
   "protocol_stack":{
      "name":"iec104server",
      "version":"1.0",
      "transport_layer":{
         "bind_on_ip":false,
      "t0_timeout":10,
               "srvt1_iptimeout":"0.0.0.0"15,
               "portt2_timeout":240410,
         "tls":false,
         "kt3_valuetimeout":12,20
          "w_value":8,  }
         "t0_timeout":10],
         "t1bind_on_timeoutip":15false,
         "t2srv_timeoutip":10"0.0.0.0",
         "t3_timeoutport":202404
      },
      "application_layer":{
         "orig_addr":"0",
         "ca_asdu_size":2,
         "ioaddr_size":3,
         "asdu_size":0,
         "time_sync":false,
         "comm_exec_timeout":20000,
         "comm_recv_timeout":5000,
         "tsiv":"IGNORE",
         "reset":false,
         "filter_orig":false,
         "filter_list":[
            {
               "orig_addr":1
            },
            {
               "orig_addr":2
            }
         ]
      }
   }
} 

IEC 104 datapoint representation

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