Control Engineering

6/25/2007
June 26, 2007

Continuing on with our discussion of items to be considered for incorporation into the master plan for the City's wastewater systems monitoring and control, this time looking more at the top three on the technical side:

4. Open architecture

      Recommendation: Base design on the most widely adopted open communication standards and protocols

         Control systems are purchased over many years on various
         contracts, typically resulting in several vendors of RTUs, PLCs,
         and communication devices.  All these must inter-operate easily,
         completely and reliably for the master plan's vision of an
         integrated system to remain a reality.
         While public bid laws typically don't allow sole sourcing,
         limiting to two has worked in the past.
         Growing industry standards to consider: Ethernet, TCP/IP, XML,
         Modbus TCP or Ethernet IP, SQL

5. Universal Access

      Recommendation: Architect system so SCADA data can cost-effectively be made available wherever it is needed

         Taking advantage of the City's existing IT infrastructure using
         Ethernet TCP/IP networking and web browsers for data access
         greatly expands the reach of SCADA at a low per user cost.
         Many local law enforcement vehicles are Internet-enabled. We are
         rapidly moving toward the majority of cell phones being
         Internet-enabled. The architecture should support mobile access
         and the cell phone becoming the "Swiss Army Knife" of maintenance
         personnel in the not so distant future.
         While municipal wastewater doesn't have the security needs of
         universal access systems distributing banking or law enforcement
         data, a level of security appropriate to the application is
         required.

6.  Master Plan Implementation

      Recommendation: Choose a long-term partner to assure master plan implementation

         This partner provides the specialized knowledge required to assure
         hardware and software from chosen vendors is selected and applied
         in accordance with the master plan.
         Ideal candidates are vendor-independent control and information
         system integrators well expereienced in municipal wastewater as
         well as the hardware and software systems likely to be employed.
         Professional services contracts can be used to ensure long term
         continuity.
         City should retain control of documentation and software (per #1
         above) to assure master plan implementation can readily be
         transferred to an alternate system integrator if required.

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