Modbus to IEC-104 conversion

ARC600 provides support for generic Modbus RTU and

Modbus TCP devices such as ABB’s RIO600. In addition,

support is also provided for the preselected Modbus

parameters for Fault Passage Indicators (FPI). Currently,

Horstmann Compass B and Kries IKI-50 are supported.

ARC600 polls the fault indicator devices, connected to the

serial port, using Modbus protocol and converts the values to

IEC 60870-5-104. Up to four fault indicators can be

connected to one device. IEC 60870-5-104 is used to

communicate towards a SCADA via the Arctic M2M Gateway

over the available customer chosen cellular data network.

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.