IEC-101 to IEC-104 conversion

With ARC600. conventional IEC 60870-101 serial devices can

be attached to a modern TCP/IP based IEC 60870-5-104

control system. This is enabled by the protocol conversion

from IEC 60870-5-101 to IEC 60870-104. In this case,

ARC600 (IEC-101 master) uses local synchronous data

polling where it continuously sends requests and the IEC-101

device (IEC-101 slave) responds. In the direction of the

control room, the communication protocol is IEC-104 and

ARC600 can send events asynchronously as they arise while

SCADA performs only slow-period background scans.

Another advantage of the local protocol conversion is an

advanced data acknowledgement mechanism. IEC-104

allows multiple packets, and multiple events in a single

packet, to be acknowledged collectively and the packets can

be buffered up to the time of acknowledgement from SCADA.