COMOS vs PCS 7 Integrated Engineering with Templates, CMT

COMOS and PCS 7: Positioning in the Plant Engineering Chain

COMOS is the Siemens platform for integrated plant engineering across process, instrumentation and control (I&C), electrical, and automation design. SIMATIC PCS 7 is the distributed control system (DCS) that executes the resulting automation logic. The two are not competing tools; they are layered components of the same engineering chain. COMOS owns the design intent (what the plant must do), PCS 7 owns the execution (how the AS 410 / AS 410E controllers actually run the plant).

Engineers who only see the COMOS authoring path of attaching Control Modules tag-by-tag to individual Positions frequently conclude that COMOS is slower than authoring directly in the PCS 7 CFC / SFC editor. That conclusion is correct when the workflow is single-tag, single-engineer, one-off project. It is incorrect when the workflow is template-driven, multi-discipline, multi-user, and re-used across multiple PCS 7 releases. This reference covers the features that turn COMOS from a documentation tool into an engineering multiplier.

Reusable Templates: Control Module Types and Equipment Module Types

The first feature most engineers never see in COMOS is the template layer. A Control Module Type (CMT) is a reusable, parameterised logic block that encapsulates the interlocks, analog processing, motor block, valve block, PID, or custom control scheme for a class of plant objects (e.g., a centrifugal pump, a control valve with permissive, a heat-exchanger outlet temperature loop). An Equipment Module Type (EMT) encapsulates a sequential procedure built in SFC and exposed through a command / status interface to higher-level control.

Once a CMT exists, instantiating a centrifugal pump in the I&C layer is a matter of dropping the template on a Position and assigning parameter values (P&ID tag, IO address, motor nameplate, trip class). The same CMT can be applied to 200 pumps across 10 process units with the same one-time engineering cost.

Pluggable Logic and Drag-and-Drop Reproduction

Pluggable logic is the COMOS mechanism for capturing an interlock or analog condition as a named, parameterised object that can be reused across CMTs and across Positions. The library model is the same conceptual layer as PCS 7's master data library, but applied at the design layer where it can be reused before PCS 7 is even installed.

1. Define the interlock in the CMT editor, e.g., PUMP_START_PERMISSIVE = NOT ESD AND NOT LOW_LUB_OIL_PRESS.
2. Expose the input signals as plug-in parameters on the CMT boundary.
3. Expose the output (start permissive) as a plug-out parameter.
4. When the CMT is instantiated on a Position, the engineer binds the plug-in to a real signal (e.g., the ESD pushbutton block, the low-lube-oil pressure transmitter) without re-authoring the logic.
5. Drag-and-drop the CMT across hundreds of Positions; only the binding step is repeated, not the logic authoring.

COMOS 10.1 and Later: EMT-SFC, Command/Status Interface, and Control Module Coupling

COMOS 10.1 introduced the Equipment Module Type (SFC) and improved the command / status handshake between Equipment Modules and Control Modules. This brings the COMOS data model into alignment with the ISA-88 batch model that PCS 7 has used since PCS 7 V8.0.

The practical consequence is that a complete batch procedure (recipe phases, transitions, operator prompts) can be authored in COMOS, reviewed by process engineering without a SIMATIC license, exported to PCS 7, and dropped into an SFC instance with the command / status wiring pre-routed. The PCS 7 engineer is no longer the bottleneck for sequencing changes that originate in the process team.

Multi-User Collaboration: Working Layer and Database Mechanisms

COMOS uses a layered database model that allows multiple engineers to work on the same project concurrently without overwriting each other. The active working layer is the engineer's private workspace. Changes are committed back to the base database only after engineering review.

Standard PCS 7 (without a PDM / iDB bridge) does not offer a comparable concurrent-engineering model: the CFC / SFC and HW Config databases are single-master file copies, often held in a source-control system by the integrator. COMOS is the right place to keep the multi-user concurrent work, with PCS 7 receiving a synchronised, reviewed snapshot at commit time.

System-Neutral Definition and PCS 7 Version Portability

One of the strongest commercial arguments for COMOS is that the automation logic is authored system-neutral: a CMT does not know whether the destination is PCS 7 V8.0 SP1, V8.1, V8.2, or V9.x. The same template library can be re-deployed to a different PCS 7 release without re-authoring the logic.

• Author the CMT once in COMOS against an abstract signal model (tag name, engineering units, range, alarm limits).
• Map the abstract model to a specific PCS 7 release at export time via the iDB / AdvES interface.
• Re-export against a different PCS 7 release in a later phase of the project; the CMT does not change.

Bulk Engineering: Import, Export, Query, Scripting

Bulk engineering is the COMOS toolset for handling data in volume. The four pillars are import, export, query, and scripting.

A realistic bulk-engineering flow looks like this:

1. Receive the I&L list from the EPC or process licensor as an Excel sheet. Columns include tag, P&ID, service, IO type, range, units, hazardous-area classification.
2. Import the sheet into COMOS I&C. Each row becomes a Position with attributes mapped to the COMOS base data.
3. Run a Query that classifies each Position by P&ID discipline and assigns a CMT (e.g., control valve, on-off valve, motor, transmitter).
4. Instantiate the assigned CMT on each Position. The plug-in / plug-out parameters are pre-bound to the Position's attributes.
5. Export the project to PCS 7 via the iDB / AdvES interface. CFC charts are generated automatically from the CMT instances.

Advanced ES (AdvES) Interface to SIMATIC PCS 7

Advanced ES is the COMOS add-on that closes the loop to PCS 7. It performs the bidirectional transfer between the COMOS database and the PCS 7 project, including the HW Config, CFC / SFC, and WinCC components.

For the round-trip to be deterministic, the COMOS side must own the canonical tag list. PCS 7 then becomes a downstream consumer rather than the source of truth. This is the standard pattern in EPC projects that have adopted integrated engineering.

P&ID and I&C Integration: From Piping to Logic

The COMOS P&ID editor is the single source of truth for equipment, lines, and instrumentation. From a single piece of equipment, the engineer can navigate to its I&C datasheet, the loop it participates in, the CMT instance on its control tag, and ultimately the PCS 7 CFC chart that runs on the AS. This single-click traceability is the core benefit of integrated engineering and is not available in any other mainstream DCS toolset.

Hardware Export: ET 200, AS, and MLFB Assignment

AdvES will generate the PCS 7 HW Config directly from the COMOS hardware model. For each Position with an assigned CMT, the engineer specifies the desired ET 200 station (head module MLFB), IM module, and SM modules (digital / analog in / analog out). On export, AdvES creates the ET 200 station under the AS, populates the slots, and assigns the IO addresses that the CMT instances will bind to.

Implementation Workflow: First-Time Setup

The recommended path for a team adopting COMOS on a new PCS 7 project is:

1. Baseline the CMT library. For each discipline (motors, valves, PID loops, sequences), build a CMT with full interlock, alarm, and IO assignment. Aim for 80% of all Position types to be covered by a CMT before any project work begins.
2. Define the import schema. Standardise the Excel / CSV columns that the project will accept. Suppliers and process licensors deliver to this schema, not the other way around.
3. Configure the iDB / AdvES mapping. Map COMOS signals to the target PCS 7 release (V8.0 SP1, V8.1, V9.0, etc.) and to the target AS family (AS 410, AS 410E, AS 410E F).
4. Build a pilot unit. Pick one process train, drive it end-to-end through the bulk engineering flow, and verify the resulting PCS 7 CFC / SFC compiles cleanly and passes the OS picture round-trip.
5. Scale the workflow. Once the pilot passes the QA gate, replicate across the remaining units. Expect engineering hours per tag to drop by a factor of 5 to 10 relative to the manual PCS 7-only approach.
6. Lock the design at commit time. Use the working-layer review to freeze the design before the integrator begins site implementation.

Comparison: COMOS-Authored vs Manual PCS 7 Engineering

Troubleshooting Matrix: Common COMOS Adoption Pitfalls

Official Siemens References

• Siemens COMOS product page - product overview and lifecycle positioning
• COMOS in Siemens Industry Online Support - manuals, downloads, FAQ for current COMOS releases including 10.1 and later
• SIMATIC PCS 7 - Service Support and Download Portal entry - PCS 7 documentation hub used as the round-trip target
• Integrated Engineering with COMOS and SIMATIC PCS 7 - application example - canonical reference for the round-trip flow described in this article