Spontaneous data communication and general query

The sample program presented here shows an IEC 60870-5-104 slave with High Level interface and a simple communication of two data points. One data point is transferred spontaneously in control direction, the other in monitor direction. In addition, a general interrogation is configured for the data point in monitor direction.

In the sample, the following parameters are set for the substation (slave):

• Server Host address (IP address of the slave/your own IP): 127.0.0.1 (At least this parameter must be adjusted individually)
• Server port address (port address of the slave/own port): 2404
• k: 12
• w: 8
• t0: 30 s
• t1: 15 s
• t2: 10 s
• t3: 20 s
• General ASDU address: 3
• Cause of transfer size: 2 octets
• Common ASDU address size: 2 octets
• Information object address size: 3 octets
• Max. APDU length: 253

The applications represent an exemplary implementation of the High Level interface. We make no claim to completeness and correctness. Set the IP address of the slave, both in the master part and in the slave part! Verify that port 2404 is not blocked by a firewall! The connection is established after the start of the program. The data points are managed in the Global Variable List (GVL).