SCADA Protocol Upgrade

integratedSCADA recently assisted TasNetworks achieving a milestone in removing legacy SCADA protocols from service.

The last substation site using Conitel C2020 protocol was successfully upgraded to DNP3 protocol. The Conitel protocol was developed by Leeds & Northrup for Master/Slave SCADA communication. The protocol as historically used by TasNetworks is a bit-orientated half-duplex serial protocol. Bit orientated protocols such as Conitel cannot be easily used with typical serial communication equipment designed for byte-orientated communication.

Dedicated non-standard devices are generally required in installations using bit-orientated protocols to convert to bytes for serial transmission. The particular device used by TasNetworks was Modem Extension Unit (MEU) or known informally as ‘bit-bashers’, manufactured by Open Systems International (OSI). Following the successful upgrade of the last substation North Hobart from Conitel C2020 to DNP3 the ‘bit-bashers’ can be decommissioned from service.

The upgrade performed onsite involved decommissioning a legacy GE D20M++ RTU and commissioning a GE D20ME RTU utilising DNP3 communications protocol. The existing legacy D20M++ had a number of peripheral boards connected including input, output and control hardwired IO. In order to migrate peripheral boards to newer GE D20ME RTU the PCOMMON EPROM chips were replaced with a later compatible version. The PCOMMON EPROM contain the firmware code or applications required for peripheral board.

All inputs, outputs and analogs were tested back to TasNetworks control centre, using planned isolation and injection methods.