Connecting Siemens WinAC on SIMATIC Microbox PC to AVEVA InTouch

Overview

Replacing an aging panel PC with a SIMATIC Microbox PC running WinAC while keeping the same AVEVA (formerly Wonderware) InTouch SCADA is a common modernization path in brownfield plants. The core question is whether a software PLC behaves like a hardware S7-300 to external HMI software. The short answer: yes — WinAC presents the same S7 communication interfaces (PROFINET, PROFIBUS DP, TCP/ISO-on-TCP, MPI, OPC DA/UA) that a physical CPU 317 does, with the same fetch/write semantics visible to OPC and DAServer clients.

This reference walks through the three viable integration paths between a WinAC RTX/PLC runtime on a Microbox IPC and AVEVA InTouch:

1. Native S7 TCP via DAServer for Siemens (DASS7) — the lowest-friction path.
2. OPC DA bridge (WinAC OPC server) to InTouch OPCLink — useful where the InTouch node already trusts a local OPC DA source.
3. DASABCIP (CIP/Ethernet/IP) — viable only when the S7-300 firmware exposes the optional “S7-CIP” interface, which 31x CPUs do not by default.

The decision tree favors DASS7 for new builds, OPC DA for legacy Wonderware nodes, and DASABCIP only when the PLC side already runs an AB or third-party controller alongside the S7.

Architecture and Topology

A WinAC installation on a Microbox PC is, from the network's perspective, indistinguishable from a physical S7-300 station. The WinAC RTX runtime binds to a real-time extension of Windows and exposes its process image through the same S7 communication stack that a CPU 315/317 would use. From InTouch's standpoint, the only difference is the rack/slot metadata: a WinAC slot is reported as PC station type “WinLC” or “WinAC RTX” instead of physical S7.

Either the DAServer or the OPC bridge may be co-located on the Microbox PC or installed on a separate SCADA node. Co-location minimizes latency but reduces the SCADA tier's portability; the recommended pattern is to run the DAServer on the SCADA server and let InTouch access it through the platform's native access name mechanism.

WinAC Software PLC Fundamentals

WinAC is Siemens' Windows Automation Center — a software PLC family available in three variants relevant to a Microbox deployment:

For an S7-300 replacement on a Microbox PC, WinAC RTX is the supported choice. Its PROFINET stack is identical to a CPU 317-2 PN/DP and is configured from the same STEP 7 or TIA Portal hardware catalog (under PC Systems → WinLC RTX / WinAC RTX). When InTouch or a DAServer queries for rack/slot it sees a slot 0 PC station with type “WinLC RTX” rather than a physical 317 — most S7 DAServers handle this transparently.

Communications available on WinAC

• TCP/ISO-on-TCP (port 102) — used by DASS7, SIMATIC NET OPC, and TIA-portal online functions.
• PROFINET IO (RT/IRT) — controller role, used for distributed I/O on ET 200S/SP/PN.
• PROFIBUS DP master — requires CP 5601/CP 5611 PCI/PCIe card in the Microbox.
• OPC DA 2.05 / 3.0 — embedded WinAC OPC server, accessible locally on the Microbox.
• S7 MPI — exposed via PC adapter or internal virtual bus for legacy STEP 7 programming.

SIMATIC Microbox PC Hardware Platform

The SIMATIC Microbox product line (IPC227G, IPC277G, IPC427G, IPC627G depending on generation) is Siemens' fanless compact IPC designed for cabinet-mount and edge use. Important characteristics for WinAC deployment:

A two-NIC topology is strongly recommended. The first NIC carries PROFINET to ET 200 stations (real-time, isolated); the second NIC carries the plant Ethernet that reaches the SCADA server. Do not route PROFINET and plant traffic over the same physical port — the DCP/discovery frames will interfere with InTouch's polling.

AVEVA InTouch HMI Architecture

AVEVA InTouch HMI is the operator visualization layer in the AVEVA PI System / System Platform stack. From a connectivity standpoint it is data-source agnostic: any server that exposes tags through one of InTouch's supported I/O mechanisms can be used.

InTouch's Access Name concept binds a tagname prefix to a network node + protocol. In a WinAC project the typical pattern is one Access Name per PLC and one Access Name per OPC source if mixing protocols.

Communication Path Comparison

Prerequisites

Before commissioning the integration, verify that the following hardware, software, and licensing components are in place.

Hardware

• SIMATIC Microbox PC (IPC227G or newer) with two physical GbE ports and an SSD.
• Plant network switch reachable from the SCADA server (managed, with IGMP snooping disabled on PROFINET VLAN).
• SCADA server with a fixed IP and adequate resources to run the AVEVA DAServer (minimum: 4 GB RAM, Windows Server 2016 or newer).

Software

• Windows 10 IoT Enterprise LTSC 2019 or 2021 on the Microbox.
• WinAC RTX 2023 or current release, installed with RTX64 runtime.
• STEP 7 V5.7 or TIA Portal V18+ with the WinAC RTX HSP installed.
• AVEVA System Platform 2020 R2 or newer, including InTouch and the DAServer for Siemens (DASS7).

Licensing

• WinAC RTX license key (Automation License Manager, USB or software-bound).
• AVEVA DAServer runtime license (per server).
• InTouch runtime license for each ViewApp / WindowViewer node.

Step-by-Step: Configuring WinAC RTX on the Microbox

1. Install RTX64. Reboot when prompted. Verify the RTX64 service is running:
   sc query RTX64Svc — state must be RUNNING.
2. Install WinAC RTX. During setup, select “WinAC RTX” and the matching PROFINET option (CP 1625/1628 or onboard Intel).
3. Activate the license via Automation License Manager; confirm the license appears in the “Effective” tab.
4. Open STEP 7 / TIA Portal and add the PC station: PC Systems → WinLC RTX. Configure slot 1 as WinLC and slot 2 as IE/PROFINET.
5. Map the PROFINET interface to the dedicated GbE port and assign the IP. Avoid overlapping the SCADA plant subnet.
6. Download the configuration (PC station → target → WinLC). The runtime starts in “RUN” once download is complete.
7. Verify WinAC is reachable from the engineering station via “Accessible nodes”. The Microbox should appear with type “PC Station (WinLC RTX)”.

Step-by-Step: Configuring DAServer for Siemens (DASS7)

1. Install the AVEVA DAServer for Siemens on the SCADA server (or co-locate on the Microbox if you accept the single-point-of-failure).
2. Launch the DAServer Manager and create a new Siemens TCP/IP port. Set the PLC IP address to the Microbox's PROFINET/plant NIC.
3. Configure connection parameters: rack 0, slot 1 (WinLC default). Set the connection type to “PG/OP” or “OP” depending on whether the engineering station will also connect through this channel.
4. Define a topic in Device Groups with a meaningful prefix, e.g. MBOX_DB.
5. Import symbols: export the STEP 7 symbol table to CSV and use the DAServer's symbol importer. Each row becomes an item with the syntax DB100.DBD0, MW10, or symbolic alias.
6. Test the connection with the built-in Server Tester. Items should turn green; failure reasons appear in the message log.
7. Activate the configuration by clicking Runtime → Save and Activate. The DAServer console will switch to “Running” state.

Sample DAServer port definition (DASPlc.ini)

[SiemensTCP]
Description = WinAC RTX on Microbox
Protocol = Siemens_TCP
PortName = S7ONLINE
HostName = 192.168.10.42
Rack = 0
Slot = 1
ConnectionType = OP
PollRate = 200
Timeout = 3000

Step-by-Step: Configuring the InTouch Access Name

1. Open InTouch WindowMaker on the engineering station.
2. Navigate to Special → Access Names and click Add.
3. Set Name to MBOX_WINAC.
4. Set Node Name to the SCADA server (or localhost if DAServer is co-located).
5. Set Application Name to DASERVER.
6. Set Topic Name to the topic defined above (e.g. MBOX_DB).
7. Choose SuiteLink as the protocol.
8. Click Save. InTouch will start reading items from the DAServer immediately.

Tag prefix example

Item:        MBOX_WINAC:TANK101_LEVEL
Tagname:     TANK101_LEVEL
Access Name: MBOX_WINAC
Item:        TANK101_LEVEL
Updates:     200 ms (matches DAServer poll rate)

Step-by-Step: Configuring the OPC DA Path (Alternative)

If SuiteLink is unavailable (e.g. very old InTouch or unsupported DAServer version), the WinAC OPC server can be exposed to InTouch through the bundled OPCLink driver.

1. On the Microbox, confirm the WinAC OPC server is registered:
   opcenum.exe → Siemens WinAC OPC Server → Server State = Running
2. On the SCADA server, launch OPCLink Explorer and connect to \<Microbox IP>\Siemens.WinACOPCServer.
3. Create an OPC Access Name in InTouch with application OPCLINK and topic default.
4. Reference tags as OPC_ACCESS:TAGNAME. OPCLink translates between OPC DA and InTouch's tag engine.

Verification

After each stage of configuration, perform a four-step verification to catch regressions early.

Quick health-check command set

# Ping the Microbox from the SCADA server
ping 192.168.10.42

# Confirm S7 TCP port is open (port 102)
Test-NetConnection -ComputerName 192.168.10.42 -Port 102

# Check WinAC runtime state
sc query WinACRTX

# Check DAServer service
sc query "AVEVA DAServer"

Troubleshooting Matrix

Security and Hardening Notes

• Disable SMBv1 and unnecessary Windows services on the Microbox.
• Place the PROFINET and plant segments on separate VLANs; the Microbox's dual NIC design supports this natively.
• Use a service account for DAServer with least privilege; do not run it as Administrator.
• Lock down port 102 with Windows Firewall to only allow the SCADA server's IP.
• Enable audit logging on the WinAC project directory to detect unauthorized program changes.

FAQ