Irrigation automation for DMT, Shakhbout

About this project

Parks and playgrounds at Shakhbout City required their irrigation pumping to be automated and brought into the client's existing supervisory system. Almafor supplied the motor control centres with variable frequency drives, the PLC and RTU panels and the instrumentation, and carried out the integration.

The important word is integration. Nothing was replaced at the supervisory layer. The client already operated an irrigation SCADA across other sites, and the requirement was that these new stations should appear inside it, behave the way the existing stations behave, and raise alarms operators already knew how to read.

That constrains the design in useful ways. Addressing, tag naming, alarm priorities and graphic conventions all have to follow what is already in service rather than what a supplier would choose from a blank sheet. A station that is technically correct but reads differently from every other station on the same screen creates hesitation at exactly the moment an operator should be certain.

Each pump room is a repeat of the same arrangement: a flow meter, a motorised valve, two variable frequency drives running three phase irrigation pumps as duty and standby, a pressure transmitter, a level transmitter, a pressure switch and a three position level switch, together with a duty and standby submersible pump and a duty and standby portable pump. Building to one pattern across the pump rooms keeps the approved submittal reusable and keeps spares interchangeable between them.

A UPS, a battery charger and lead acid batteries back the PLC and RTU at each station, so a mains interruption arrives at the control room as a reported event rather than as silence. Analogue signal splitters let a single transmitter feed both the local controller and the RTU, which is the ordinary way a local reading and a SCADA reading stop agreeing if it is not done properly.

One of the parks came back later as a replacement rather than a new installation. Its motor control centre and RTU had been damaged and were rebuilt and reinstated to the same design as the rest, which is the practical benefit of having built the pump rooms to a common pattern in the first place.

The panels were built and factory tested at our workshop in Mussafah before they reached site.