Configuring Multiuser Engineering and Dual Engineering Stations in SIMATIC PCS 7 Multiprojects

In SIMATIC PCS 7, deploying two identical Engineering Stations (two ES) to modify a complete distributed control system multiproject concurrently is achieved through Multiuser Engineering. Rather than duplicating project files manually, the Multiproject must be hosted on a central Engineering Server (or Leading ES) network share. Two operational workflows are supported: concurrent multi-user engineering across the network (where both ES stations access the shared multiproject simultaneously to edit different AS stations or separate CFC charts), and decoupled engineering using 'Remove for Editing' and 'Reapply After Editing' (where an individual AS project is checked out to a local station and merged back upon completion). To ensure system integrity, both engineering stations must run identical PCS 7 versions and libraries, share synchronized Windows user accounts within the local SIMATIC HMI group, and coordinate OS compilations from the leading station.

Architecture of Multiuser Engineering in SIMATIC PCS 7

In large-scale industrial projects, engineering deadlines necessitate multiple control engineers collaborating simultaneously. In a plant with two Automation Stations, two redundant OS Servers, and two OS Clients, having two dedicated Engineering Stations (ES 1 and ES 2) allows hardware configuration, control chart design, and graphic engineering to proceed in parallel.

SIMATIC PCS 7 manages collaboration through Multiuser Engineering:
- A single master Multiproject container groups all individual sub-projects (AS 1, AS 2, OS Server, OS Client) and the central Master Data Library (MDL).
- The Multiproject is physically stored on the hard drive of the designated Engineering Server (Leading ES) and shared across the dedicated Engineering LAN.
- Client engineering stations connect to the network share, opening sub-projects directly within their local SIMATIC Manager sessions.

Workflow 1: Concurrent Engineering Across the Multiproject Network

In this mode, both engineering stations remain connected to the high-speed engineering network and access the shared multiproject concurrently:

Operational Rules:

Station-Level Concurrency: Engineer 1 on ES 1 can open and edit AS 1 (HW Config, CFC, SFC, download) while Engineer 2 on ES 2 simultaneously opens and edits AS 2.
Chart-Level Object Locking: Within a single AS station, both engineers can open the same Charts folder. However, SIMATIC PCS 7 enforces strict object locking:
- If Engineer 1 opens chart CFC_Reactor101, the system places a software lock on that chart.
- If Engineer 2 attempts to open CFC_Reactor101, CFC opens the chart in Read-Only Display Mode with editing controls disabled.
- Engineer 2 can open and edit any other chart (e.g., CFC_Boiler201) in the identical AS station without restriction.
Cross-Project Interconnections: Interconnections between charts residing in AS 1 and AS 2 are automatically coordinated across the shared multiproject database.

Workflow 2: Decoupled Engineering via 'Remove for Editing'

When an engineer must take an AS project offline—such as commissioning an isolated unit in the field using a portable laptop without network access to the engineering server—the Check-Out / Check-In workflow is utilized:

Step 1: Remove for Editing (Check-Out)

On the Leading ES, open SIMATIC Manager.
Select the AS project to be modified (e.g., AS 2).
Select menu File > Multiproject > Remove for editing....
Specify a local destination or portable drive.
The project is decoupled from the master multiproject:
- In the central Multiproject, AS 2 is flagged with a padlock icon, signifying it is checked out for editing.
- Other engineers can view the checked-out project in read-only mode, but cannot modify it.

Step 2: Field Modification and Commissioning

The engineer connects directly to AS 2 in the field, making logic changes, compiling, and downloading code.

Step 3: Reapply After Editing (Check-In)

Reconnect the engineering laptop to the engineering network.
On the Leading ES, select the Multiproject root.
Select menu File > Multiproject > Reapply after editing....
Select the modified project.
The synchronization engine inspects structural changes, updates cross-project signal pointers, integrates the modified charts back into the central Multiproject, and removes the padlock icon.

Roles and Responsibilities: Leading ES vs Secondary ES

To avoid database corruption, certain administrative tasks must be strictly reserved for the Leading Engineering Station:

Engineering TaskPermitted on Leading ES (Server)Permitted on Secondary ES (Client)Operational ReasonCFC / SFC Chart EditingYesYesSupported concurrently with object lockingHW Config ModificationYesYes (one station at a time)Station-level lock enforcedAS Program DownloadYesYes (to assigned controller)Direct download over plant busMaster Data Library UpdatesYes (Exclusive)Read-Only AccessPrevents library version driftWinCC OS CompilationYes (Recommended)RestrictedRequires exclusive write access to SQL databaseMultiproject ArchivingYes (Exclusive)ProhibitedArchiving requires all sub-projects closed

Verification

To confirm that multiuser engineering functions reliably across both stations:
1. On ES 1, open AS 1 and open a CFC chart: Verify full editing access.
2. On ES 2, open AS 2 and open a different CFC chart: Verify full editing access.
3. On ES 2, attempt to open the identical chart currently open on ES 1: Confirm that CFC displays a notification: Chart is opened by another user. Opening in read-only mode.
4. Close the chart on ES 1: Confirm that ES 2 can now open the chart with full editing rights.
5. In SIMATIC Manager on ES 1, initiate a Changes-only OS compile: Confirm that tags from both AS 1 and AS 2 compile successfully into the WinCC database.

Limitations and Operational Precautions

Observe the following engineering precautions:
- Identical Software and Hotfixes Mandatory: Both engineering stations must run identical PCS 7 versions, identical Service Packs, and identical Hotfixes. Mixing CFC versions (e.g., CFC V8.2 on ES 1 and CFC V8.2 Upd1 on ES 2) will corrupt chart headers.
- Dedicated Engineering Network: Do not run multiuser project sharing over Wi-Fi or congested plant bus networks. Use a dedicated, low-latency Gigabit Ethernet engineering switch.
- Windows User Authentication: Both stations must belong to the same Windows Active Directory domain or maintain identical local user accounts and passwords, with users added to the local SIMATIC HMI and Administrators groups.

Engineer FAQ

Can two engineers edit the same CFC chart simultaneously?

No. PCS 7 enforces object-level locking on individual CFC and SFC charts. The first engineer to open the chart obtains exclusive write access; subsequent engineers can only open the chart in read-only mode.

Can both engineering stations compile the OS?

While technically possible if the OS project is closed on the other station, Siemens best practice dictates that OS compilation and Master Data Library management should be performed exclusively from the Leading Engineering Station.

What happens if network connection is lost during concurrent editing?

If network connectivity between the secondary ES and the engineering server is lost, unsaved changes in the open CFC editor buffer may be lost, and temporary lock files (*.lok) may remain on the server, requiring a reset or manual lock deletion.