Retrofitting an ALSPA P320 system becomes appropriate when the expected remaining operating life, technical risks or plant objectives justify migration to a new platform. The challenge is not simply to replace controllers and workstations: protections, sequences, control strategies, interfaces and operating modes that govern the actual process must be preserved.
Through its in-depth knowledge of ALSPA P320 and commissioning experience, ICSS can support both the operator and the supplier of the new system, from analysis of the existing installation through testing and start-up of the upgraded plant.
Understand the existing system before defining the target
Available drawings and I/O lists do not always reflect the latest project state. Functions may have been added to the Controcad database, exchanges modified on site, or specific conventions incorporated during successive commissioning activities. The study must therefore start from the projects actually loaded and compare their content with the hardware architecture, documentation and plant behaviour.
This analysis identifies visible functions as well as less obvious mechanisms: tracking, initialisation, degraded modes, protections, switchover sequences, quality processing, communication with third-party systems and site-specific operating dependencies.
Manage process risk during migration
The hardware migration of I/O is often the best-controlled part of a retrofit. Adapter boards frequently connect the new system to existing wiring and marshalling while limiting field modifications. This hardware continuity does not, however, guarantee that plant behaviour will be reproduced correctly.
The main risk lies in reimplementing sequences, control strategies, protections, initialisation, degraded modes and interactions between systems. A team may have complete command of the new platform without knowing the historical reasons behind a logic function or its effects on the process. Differences then emerge during hot testing or restart, when every function must once again operate correctly within the plant as a whole.
In England, ICSS encountered a restart planned for three weeks that extended to almost three months, followed by difficulties that remained after the unit returned to service. This experience shows why an upgrade decision must compare project risk with the risk of retaining the existing system, and why a justified migration must combine knowledge of the source system, process understanding and commissioning experience from a very early stage.
ICSS support specifically aims to reduce this area of risk: identify implicit functions before conversion, verify functional equivalence, prepare representative tests, analyse differences during start-up, and help the operator, integrator and process specialists quickly resolve issues spanning several systems.
Automatically extract P320 project data
ICSS has developed a library of more than 90 SQL and Perl scripts capable of querying ALSPA P320 project databases directly. These tools have been used to prepare retrofit estimates and projects by producing structured, consistent and reproducible data from the actual configuration.
- Inventory of physical I/O, including spare channels, board references, addresses, scales, units and states.
- Controller, board and channel parameters, together with hardware-architecture configuration.
- Modbus, UnitBus, HMI and ICCP exchanges, including direction, functions used, addresses and associated variables.
- Variables used in function diagrams, blocks, programs, execution orders and controllers.
- Constants, settings, arrays, alarms, event logs, archives and information intended for the HMI.
Automation reduces omissions and avoids extensive manual re-entry. It does not replace engineering analysis: extracts must be checked, compared with drawings and interpreted in light of the process and site-specific features.
Support the operator and the new-system supplier
For the operator, ICSS can contribute to the initial assessment, specifications, definition of functional equivalence, bid analysis and verification of the proposed solution. This assistance helps distinguish functions that must be retained unchanged from those that can be simplified or improved.
ICSS has also supported system suppliers, including Siemens and Emerson, in understanding P320 projects, automating extraction of the required data, preparing mappings to the new platform, and addressing specific features discovered during integration or commissioning.
Experience migrating ALSPA P320 to Emerson Ovation
Experience gained at Combigolfe, Cycofos and DK6 covers different stages of combined-cycle power-plant migration projects to Emerson Ovation:
- Combigolfe, Fos-sur-Mer —
KA26424 MW combined-cycle power plant. - Cycofos, Fos-sur-Mer —
KA26400 MW combined-cycle power plant. - DK6, Dunkirk — two
KA13E2400 MW combined-cycle units, including assistance to Emerson with replacing the ALSPA P320 system with Ovation.
These projects demonstrate the value of a specialist who can read P320 logic with the insight of a former manufacturer engineer while understanding the constraints of the new system, the process and recommissioning.
Preserve the function without copying blindly
A functionally equivalent migration does not mean reproducing every historical detail without review. It aims to preserve useful and safe plant behaviour while using the new system to clarify selected functions, remove unnecessary dependencies and improve maintainability where the risk is controlled.
Combined process and control-system expertise makes it possible to verify that logical equivalence produces the same physical effect. This is particularly important for sequences, control strategies, protections, permissives and degraded modes whose behaviour cannot be validated by simply comparing lists.
Prepare the switchover, testing and return to service
Preparation includes an inventory of wiring and communications, the strategy for coexistence between old and new systems, simulations, FAT and SAT testing, I/O checks, team training, outage phasing and rollback criteria. Tests are organised to verify individual functions and then their coordination across the whole plant.
During commissioning, ICSS can help analyse differences between expected and actual behaviour, adjust sequences or control strategies, and facilitate dialogue between the operator, integrator and process specialists.
Define an appropriate scope
The project may involve complete replacement of the control system, a phased migration or temporary coexistence of several platforms. The initial study must compare cost, outage risks, expected operating life, testing opportunities and available expertise to select a realistic scope. Where replacement is not yet justified, a strategy for P320 obsolescence management and long-term operational support may be a more proportionate alternative.
ICSS’s complementary expertise in control systems and control and regulation, combined with its field experience, supports this decision with an overall view of the plant.