Automation System Maintenance for DCS & SIS
Maintenance approach
Preventive maintenance
Ensuring continuous operation of a plant depends on the control system staying available. One of the most significant threats is a failure inside the control system. A planned maintenance strategy reduces production slowdowns and complete stoppages from DCS, ESD or historian faults.
Preventive maintenance is scheduled and interval-based: maintenance scheduling and implementation against a plan agreed with site personnel.
Condition-based maintenance
Maintenance work is targeted and condition-based: improve the efficiency, reliability and service life of your automation systems by acting on measured condition rather than on a calendar alone.
Effective maintenance starts with an audit of systems and devices. Using accurate and up-to-date condition data, we identify the actions required, when and where they apply, and eliminate unnecessary tasks.
System and device assessment supports that audit. On the refinery CHP plant we have maintained DCS, ESD, BMS and MES continuously since 2022, and for eleven years before that from 2007 to 2018.
Corrective and emergency support
Maintenance is essential for mitigating control system risk, including corrective work after a failure.
- Service calls
- On-demand support
- Emergency visit
Remote support
On-site and remote support for control systems already running in production.
Performance monitoring
- Improve process performance while reducing costs
- Minimise safety and environmental risks
- Extend the service life of installed systems
Control loop performance is monitored continuously, loops are retuned, and alternative control strategies are implemented where the existing one limits the unit.
Platforms in maintenance
- ABB Industrial IT 800xA
- Emerson Ovation
- HIMA HIQuad
- Siemens PCS7
- Siemens TIA Portal
- Yokogawa Centum VP
Performance calculation and reporting
Alongside condition-based maintenance, we implement the calculations that show whether a plant is performing as designed:
- Boiler efficiency by direct and indirect method, for gas-fired and petroleum coke fired circulating fluidized bed boilers
- Steam turbine efficiency and losses
- Thermal balances and electrical energy balances
- Process data collection from control systems and commercial metering units, with long-term archiving
Maintenance on a generating plant is a test programme
An inspection round tells you that a system looks healthy. On a generating plant that is not enough, because the functions that matter are the ones that have not run since the last time anybody made them run.
On the hydro plant we maintain, each quarterly visit puts two engineers on site for a week, and the programme includes proving, on the running or shutdown machine as appropriate:
- the emergency shutdown chain, including the shield release command
- the shutdown sequences, step by step
- overspeed protection
- compliance with the governing guarantees, by load rejection
- the power controller while synchronised to the grid
- the frequency and power controller, by load rejection
- the frequency and power controller with the plant transferred to an isolated district
- the vibration and shaft runout channels against the protection logic, not merely read
Alongside that, the things that are only discovered by measuring them: battery capacity in the uninterruptible supplies, proved by running them down for at least 30 minutes rather than reading a status lamp; the stored-energy cabinets that close the guide vanes when everything else is gone; failover of the redundant control network and the redundant supply, proved by breaking each; time synchronisation across the system against the GPS reference; and a restore from backup that is actually performed.
Where a failure stops the machine or breaks the exchange of data with the system operator, we are on site within 24 hours of the notification.
Island mode and the testing behind it are covered under Island Mode Operation. The vibration side is under Hydro Vibration and Shaft Monitoring.