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IEC 104 Client (Master)

Client (Master) modunda inSCADA, saha istasyonlarına (RTU, IED, koruma rölesi vb.) bağlanarak veri okur ve kontrol komutları gönderir.

ParametreÖrnekAçıklama
ProtocolIEC 60870-5-104Protokol seçimi
IP Address192.168.1.50Hedef slave istasyon IP adresi
Port2404Hedef port (varsayılan: 2404)
COT Field Length2Cause of Transmission alan uzunluğu (1-2 byte)
Common Address Field Length2CASDU alan uzunluğu (1-2 byte)
IOA Field Length3IOA alan uzunluğu (1-3 byte)
Originator Address0Master originator adresi
t115 snYanıt bekleme timeout’u
t210 snS-format onay timeout’u
t320 snTest frame timeout’u
k12Maks. onaylanmamış I-frame
w8Onay penceresi
Is With TimestampstrueZaman damgalı ASDU’ları kabul et
Background Scan Period60000 msBackground scan periyodu
Spontaneous Duplicates0Spontaneous mesaj tekrar sayısı
Use System TimezonefalseSistem zaman dilimini kullan
ParametreÖrnekAçıklama
Common Address1CASDU — slave istasyon adresi
Control Point Offset0Kontrol komutu adres ofseti
Scan Time1000 msTarama periyodu
Scan TypePERIODICPERIODIC veya FIXED_DELAY

Her ASDU tipi için bir Frame tanımlayın:

ParametreÖrnekAçıklama
TypeMeasured Value, Short FloatASDU tipi
Frame AdıTypeKullanım
Dijital GirişSingle Point InformationKesici/ayırıcı durumları
Çift DijitalDouble Point InformationKesici pozisyonları (açık/kapalı/geçiş/belirsiz)
Analog ÖlçümMeasured Value, Short FloatAkım, gerilim, güç ölçümleri
Normalize ÖlçümMeasured Value, Normalized±32767 aralığında tam sayı ölçümler
Ölçekli ÖlçümMeasured Value, ScaledÖlçeklenmiş tam sayı ölçümler

IEC 104 değişkenleri IOA (Information Object Address) ile tanımlanır:

ParametreÖrnekAçıklama
Use IOA AddressestrueIOA adresleme modu
Read Address100Okuma adresi (basit mod)
Write Address100Yazma adresi (basit mod)
Read IOA Address 10IOA okuma adresi byte 1
Read IOA Address 20IOA okuma adresi byte 2
Read IOA Address 3100IOA okuma adresi byte 3
Write IOA Address 10IOA yazma adresi byte 1
Write IOA Address 20IOA yazma adresi byte 2
Write IOA Address 3100IOA yazma adresi byte 3

In inSCADA, an IEC 104 variable can have both a Read Address and a Write Address. Correct usage of these two addresses is critical for efficient configuration.

Basic rule: If you only enter a Write Address for a variable, you cannot see the written value on inSCADA screens — because no read address is defined.

In the IEC 104 standard, reading (monitoring) and writing (control) for the same data point use different ASDU types. However, the IOA address can remain the same — because the ASDU type is determined by the Frame type. inSCADA automatically knows which ASDU type to use:

OperationASDU TypeType GroupDirection
ReadM_SP_NA_1 (TI 1)Single Point InformationMonitoring
Read (timestamped)M_SP_TB_1 (TI 30)Single Point InformationMonitoring
WriteC_SC_NA_1 (TI 45)Single CommandControl
Write (timestamped)C_SC_TA_1 (TI 58)Single CommandControl

Notice: These all belong to the same Single Point data group. The only difference is whether it is monitoring (M_) or control (C_) and whether it includes a timestamp. Therefore, you can enter the same IOA address for both Read and Write:

Variable: "Breaker_1"
├── Read Address: 100 ← Read as M_SP_NA_1 (Frame type determines this)
└── Write Address: 100 ← Written as C_SC_NA_1 (Frame type determines this)

inSCADA automatically selects the correct ASDU type by looking at the Frame type the variable belongs to:

  • Frame type Single Point Information → M_SP_NA_1/TB_1 for reading, C_SC_NA_1/TA_1 for writing
  • Frame type Measured Value, Short Float → M_ME_NC_1/TF_1 for reading, C_SE_NC_1 for writing

This means:

  • A single variable definition with the same IOA address is sufficient
  • The same address can be used for both monitoring and control on the RTU/PLC side
  • No need to create separate variables for reading and writing
  • You can see the current value on screens and send control commands from the same variable

Example — Breaker Control:

VariableRead AddressWrite AddressRead ASDUWrite ASDU
Breaker_1100100M_SP_NA_1C_SC_NA_1
Temp_Setpoint200200M_ME_NC_1C_SE_NC_1

Start the connection from the Runtime Control Panel. inSCADA will automatically:

  1. Establish the TCP connection
  2. Send STARTDT (Start Data Transfer)
  3. Start background scan (if configured)
  4. Begin listening for spontaneous events

The connection status will show “Connected”.