Deploying Multiple OpenPCS 7 Servers and Resolving OPC A&E Connection Error 0x80004005

SIMATIC PCS 7 v8.1 SP1 fully supports operating multiple OpenPCS 7 stations simultaneously in a single plant architecture. When connecting an OPC A&E client to 'PCS7.OPCAEServer.1' fails with COM/DCOM error 0x80004005 (E_FAIL), the failure is caused by a missing local OpenPCS 7 license, restrictive Windows DCOM access permissions, or unconfigured OS server packages. OpenPCS 7 requires a dedicated single-station license (6ES7658-0EX...) installed directly on each physical OpenPCS 7 server via Automation License Manager; licenses cannot be served from a remote license server.

Architecture of Multiple OpenPCS 7 Stations in PCS 7 Systems

OpenPCS 7 (6ES7658-0EX...) provides standardized interfaces (OPC DA, OPC HDA, OPC A&E, and OLE-DB) enabling external Manufacturing Execution Systems (MES), Laboratory Information Management Systems (LIMS), and third-party alarm managers to exchange process data with SIMATIC PCS 7.

An enterprise automation architecture frequently requires deploying multiple independent OpenPCS 7 stations concurrently:
* Station A: Dedicated OPC DA/HDA interface for MES recipe and production scheduling.
* Station B: Dedicated OPC A&E interface for an external emergency management or alarm annunciation platform.

PCS 7 supports multi-server OpenPCS 7 topologies without conflict, provided each station is configured as an independent PC Station in SIMATIC Manager and holds valid local software licensing.

Root Causes of OPC A&E Connection Failure 0x80004005 (E_FAIL)

When an OPC A&E client attempts to connect to PCS7.OPCAEServer.1 on a newly commissioned second server, the COM layer often aborts with error HR = 80004005 (E_FAIL / Unspecified Error):

Failure Root CauseTechnical Failure MechanismResolution CheckpointMissing Local LicenseAutomation License Manager finds no local OpenPCS 7 license key.OPC server denies client attachment; returns E_FAIL. Install license locally.DCOM Security RejectionWindows DCOM rejects cross-station Launch and Activation permissions.Configure DCOM permissions in dcomcnfg for SIMATIC HMI group.Missing Server PackagesOS Server Data packages (.pck) not downloaded to the OpenPCS 7 station.OpenPCS 7 cannot resolve AS/OS message databases without server packages.Firewall / Port BlockingWindows Firewall blocks RPC port 135 or dynamic DCOM port ranges.Run SIMATIC Security Controller to repeat security settings.

Table 1: Root causes of OpenPCS 7 connection aborts.

Single-Station Licensing Model for OpenPCS 7 Nodes

A critical licensing rule governs OpenPCS 7 deployments:
* Single-Station Licensing Only: OpenPCS 7 license keys (6ES7658-0EX...) are strictly Single Licenses. They must be transferred directly onto the physical or virtual computer where the OpenPCS 7 station executes.
* No Remote License Server: Unlike certain floating engineering licenses, an OpenPCS 7 server cannot query license keys located across the network on an Engineering Station or centralized license server.
* Every additional OpenPCS 7 node requires its own separate license key installed locally via Automation License Manager (ALM). Always validate license requirements with an authorized Siemens distributor.

Step-by-Step DCOM, User Group, and Firewall Configuration

To commission the second OpenPCS 7 station and clear error 0x80004005:

Install Local License Key:
* Open Automation License Manager (ALM) on the second OpenPCS 7 station.
* Transfer the OpenPCS 7 license key directly to the local system drive (C:).
Configure Windows User Groups:
* Ensure the Windows user running the OPC client exists on the OpenPCS 7 server.
* Add this user to local groups: SIMATIC HMI, SIMATIC NET, and Distributed COM Users.
Configure DCOM Permissions (dcomcnfg):
* Open Windows Run, type dcomcnfg, and press Enter.
* Expand Component Services > Computers > My Computer > DCOM Config.
* Locate PCS7.OPCAEServer.1 (and OPCEnum).
* Open Properties: on the Security tab, customize Launch and Activation Permissions and Access Permissions to grant Local and Remote access to group SIMATIC HMI.
Compile and Download OS Packages from ES:
* In SIMATIC Manager on the ES, insert an OpenPCS 7 Station.
* Assign OS server packages to the station.
* Right-click and execute PLC > Download to transfer the package files.

Verification

To confirm proper OpenPCS 7 operation:

On the client computer, launch an OPC test client (e.g., Siemens OPC Scout or Matrikon OPC Explorer).
Browse remote servers on the second station: verify that PCS7.OPCAEServer.1 appears in the server catalog.
Connect to the server: confirm connection establishes with return code S_OK (0x00000000) without 0x80004005.
Subscribe to the OPC A&E event stream: trigger a test alarm in PCS 7 and confirm that the event payload (Message Text, Priority, Area, Timestamp) populates the client table in real time.

Limitations and Operational Precautions

Operating OpenPCS 7 over routed WAN connections requires configuring OPC UA (OpenPCS 7 OPC UA Server) rather than classic DCOM, as DCOM does not tolerate high network latencies and NAT firewalls.
Do not disable Windows Firewall completely; run SIMATIC Security Controller to create structured firewall exceptions for OPC communication.
Ensure both OpenPCS 7 stations participate in the plant terminal bus time synchronization to guarantee coherent event timestamps.

Engineer FAQ

Can OpenPCS 7 run on an OS Client station?

Yes. OpenPCS 7 can be installed on an OS Client, OS Single Station, or on a dedicated standalone PC station connected to the terminal bus.

What is the difference between OPC DA and OPC A&E in OpenPCS 7?

OPC DA (Data Access) transfers continuous process tag values (analog/digital). OPC A&E (Alarms & Events) transmits discrete, timestamped process alarms, operator interventions, and system messages.

Does OpenPCS 7 support OPC UA?

Yes. Modern OpenPCS 7 releases include an integrated OPC UA Server supporting DA, HDA, and AC profiles over encrypted TCP channels without DCOM configuration.