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