I am looking at upgrading a mineral processing control system in Queensland Australia and would appreciate comments on the relative merits and pitfalls of each of the possible scenarios. The upgrade is due to increasing maintenance costs due to obsolecence of the installed equipment and the problems caused by the historical effects of just tacking bits on whenever a new facility was installed at the site. Its a bit of a tangle now with an extensive (and slow) network. The control equipment is spread over 30 odd facilities on site and consists of mainly allen bradley plc's of various vintages and a littleYokogawa DCS (microxl/CS3000) with 15,000 IO, around 20 plant OIT's and a control room with a half dozen OIT's and the usual mix of servers, historians, engineering workstations, networking and plant management packages. Its complicated by the fact it will need to be cutover in stages during routine facility shuts.
What it boils down to is as follows Go to fully PLC (AB) ControlLogix with RSView32 - What does this signify for the HMI compared to a DCS? Go to fully DCS - Yokogawa CS3000? Go to an updated hybrid say ControlLogix/Yokogawa CS3000 -or another vendor?
What are the options? Pitfalls? Pro's & con's? Relative costs? Repercussions for cutover/maintenance/operations/thirdparty support? Should I look at other vendors & what would they offer? Citect/Emerson/ABB....?
Whatever we do it will need to be able to be supported for a while (say to 2020?) and allow for expansion.
I would appreciate any suggestions as cutting through the manufacturers hype has been a frustrating exercise to say the least.