Siemens WinCC SCADA Licensing: Selecting TIA Portal Runtime

Selecting the correct Siemens WinCC SCADA license is one of the most common stumbling blocks for engineers building a small-to-medium supervisory system on top of a third-party PLC such as the Allen-Bradley MicroLogix 1400. The TIA Portal license catalog splits cleanly into engineering software (used to design the screens, tags, alarms, scripts, and trends) and runtime software (the executing HMI/SCADA system that runs on the panel, IPC, or PC). The runtime side is where most budget conversations stall because the price moves with the tag count, the number of clients, the option packages (recipes, logging, redundancy), and the chosen hardware platform (Comfort Panel vs. SIMATIC IPC vs. arbitrary PC).

This guide walks through the architecture, the tag-based PowerPack model, the Modbus TCP path into a MicroLogix 1400, the database/reporting requirements typical of a water-treatment SCADA, and a step-by-step procedure to size and order the correct licenses. It is written to be read at the desk with the Siemens automation software licenses page open in a browser and the WinCC (TIA Portal) license FAQ PDF printed beside the keyboard.

1. WinCC License Architecture: Engineering vs. Runtime

Every WinCC project you build in TIA Portal is supported by two independent license pools:

The two pools are decoupled. A single Engineering license (typically 6AV2100-0AA00-0AA0 for the floating/combined edition) can produce runtime projects for any number of target systems. Each runtime target, however, requires its own runtime license keyed to that machine. This is described in the official TIA Portal V20 documentation on licensing STEP 7 and WinCC.

Two practical consequences:

1. Buying a SIMATIC Comfort Panel or a SIMATIC IPC pre-flashed with WinCC RT means the runtime license is already embedded in the device's bundled article number. No separate license key is required; the user only needs the Engineering license to author the project. This is the lowest-friction path for a small, panel-bound HMI/SCADA.
2. Running WinCC RT on a third-party PC (for example, a panel-mount industrial PC from another vendor, or a desk PC in a control room) requires a separately purchased Windows license, a separately purchased WinCC RT license, and a license key installed through the Automation License Manager.

2. WinCC RT Advanced vs. RT Professional

The TIA Portal runtime family is split into two products that target very different scales:

Rule of thumb from the field:

• One operator station, one PLC, ≤2 048 tags: WinCC RT Advanced on a Comfort Panel or IPC.
• Two or more operator stations, central historian, reporting to MS SQL/SQL Server, or any >2 048 tag project: WinCC RT Professional.

The original poster's water-purification plant has one MicroLogix 1400, ~20 I/O modules on Ethernet, 10 report types, and a database sink. On paper that fits RT Advanced for a single panel. The deciding factors are (a) whether one or more operator stations are required, (b) the tag count, and (c) whether SQL Server is on the critical path.

3. Tag-Based PowerPack Licensing Model

WinCC runtime licenses are sold in "power tag" tiers. A power tag is an internal, process-relevant variable that is referenced on a screen, in an alarm, in a trend, in a script, or in a recipe. Internal helper tags and array elements are not power tags as long as they are not used in a way that counts.

Each base runtime license includes a fixed quota of power tags:

Article numbers vary by region, channel (digital vs. physical shipment), and bundle (engineering+runtime vs. runtime-only). Always re-validate against the current Siemens Industry Mall catalog before issuing a purchase order.

For a MicroLogix 1400 with 20 I/O modules, expect:

• ≈ 20 × 16 = 320 discrete I/O points, of which roughly half are inputs and half outputs.
• Add analog channels, motor starters, valve feedbacks, and instrument loops. A 20-module rack with a mix of 16DI, 16DO, 8AI, 8AO, plus a few specialty modules routinely lands at 400-700 raw I/O bits/words.
• Add derived tags for alarms, totals, rates, and engineering unit conversions. A 30-50 % overhead is normal.
• Total power tag count for such a rack: typically 600-1 000.

That fits inside the 2 048 PT RT Advanced tier with headroom. The 128 PT tier would be wrong by an order of magnitude; the 4 096 PT tier would be over-spec.

4. HMI vs. SCADA: The Architectural Question

It is worth pausing on terminology because Siemens' catalog uses "SCADA" only loosely. In the IEC 62443 / ISA-101 sense, a SCADA is a site-wide, multi-station supervisory system. In the Siemens TIA Portal world, the same word is used for any WinCC Professional project, even one with a single PC.

For the plant in the source question, the deciding architectural facts are:

• One PLC, one operator station: the natural fit is a WinCC RT Advanced project on a Comfort Panel (e.g., TP1500 Comfort, 6AV2 124-1MC01-0AX0) or an IPC227G, with the runtime license bundled.
• Multiple operator stations, central historian, MSSQL reporting: the natural fit is WinCC RT Professional on a SIMATIC IPC, with the Process Historian add-on and the Information Server add-on.
• WinCC V7: appropriate only if multi-server / multi-site redundancy, large tag counts (> 250 000), or integration with an existing V7 fleet is required. The OP does not appear to need it.

Most plants of the size described start as a single Advanced license and grow to Professional only when the second operator desk is added.

5. Connecting WinCC to a MicroLogix 1400 via Modbus TCP

The MicroLogix 1400 does not speak S7Comm/ISO-on-TCP natively, so the standard WinCC "SIMATIC S7" driver will not attach. The supported path is Modbus TCP, which the 1769-L30B/-L31/-L32/-L35 processors expose on the built-in Ethernet port (port 502, 8 connections, function codes 01/02/03/04/05/06/15/16).

Procedure in TIA Portal V17+ (WinCC RT Advanced or Professional):

1. Open the project, switch to "Devices & Networks."
2. Add a new device → "Others → Modbus TCP → Modbus TCP connection."
3. Set the MicroLogix IP address (e.g., 192.168.1.10), port 502, connection resource 0.
4. In the WinCC tag table, choose data type Modbus Holding Register (function 03) for integer data, Modbus Input Register (function 04) for analog inputs, Modbus Coil (function 01/05) for digital outputs, and Modbus Discrete Input (function 02) for digital inputs.
5. Map WinCC addresses to Modbus addresses with the standard MicroLogix offset: 4xxxx holding registers in Modbus are the integer files N7:0, N9:0, etc., with a -1 offset (Modbus register 40001 = N7:0 word 0). For bit-level access on a 16-bit word, the offset rule is the same; the bit index is appended.
6. Set the acquisition cycle to match the control loop (1 000 ms for analog trends, 100-250 ms for status, 50-100 ms only where strictly needed).

Plan for ≈ 30 % spare holding registers to absorb future I/O additions without re-mapping.

6. Database and Reporting Options

WinCC's reporting story is the area where Advanced and Professional differ most:

For a water-purification plant producing ten report types and writing to a database:

• On a single Comfort Panel, the report layout is done in the Comfort Panel's report designer; the "database" is a CSV file or a local SQLite file transferred nightly via FTP/SMB.
• On a single IPC running RT Professional, the same is possible plus a direct ODBC connection to a plant SQL Server, plus the Information Server for browser-based dashboards.
• Multi-station with central reporting absolutely requires RT Professional + Process Historian + Information Server.

7. Automation License Manager and the New License Portal

Every WinCC license is delivered as a license key (an .zip-wrapped, hardware-bound file with a .._key.txt manifest) that is installed through the Automation License Manager (ALM). The ALM runs on the engineering PC, on the runtime target, or on a separate license server on the same subnet.

Key flows:

1. Open ALM → "Start > Programs > Siemens Automation > Automation License Manager."
2. Plug the USB license stick (for bound keys) or import the file license.
3. Drag the key onto the destination target in ALM's matrix view.
4. Confirm in the target's WinCC RT "About" dialog that the active license matches the project.

From 21 October 2025, Siemens has consolidated the license delivery and management interface into a new License Portal. Existing Automation License Manager keys continue to function; new purchases and re-hosting are handled through the portal. Engineers should register their Siemens customer account on the portal before commissioning so that any re-licensing request is processed in hours rather than days.

For a deeper catalog of license types, refer to the official WinCC (TIA Portal) license FAQ PDF and the live Siemens automation software licenses page.

8. Step-by-Step License Selection Procedure

The following procedure turns the architectural choices into a definitive bill of materials:

8.1 Inventory the application

1. List the PLCs and their protocols (here: 1× MicroLogix 1400, Modbus TCP, port 502).
2. List the operator stations and their locations.
3. Count raw I/O points and multiply by 1.3-1.5 to get the projected power tag count.
4. List the optional features required: recipes, audit, SQL Server historian, web reports, redundancy, e-mail on alarm.
5. Decide the hardware platform: Comfort Panel, SIMATIC IPC, or third-party PC.

8.2 Choose the runtime family

8.3 Size the power tag tier

Round up to the next standard tier above the projected count. A 700-tag project on RT Advanced requires the 2 048 PT license, not the 512 PT license with a PowerPack — the base license is usually cheaper than a 512-base + 2 048 PowerPack combination.

8.4 Add the option licenses

• Recipes (Advanced/Professional): 6AV2107-0JA00-0AA0 family
• Audit (Advanced/Professional): 6AV2107-0KB00-0AA0 family
• Process Historian (Professional only): 6AV2107-0DH00-0AA0 family
• Information Server (Professional only): 6AV2107-0EH00-0AA0 family
• Redundancy (Professional only): 6AV2107-0LB00-0AA0 family
• SIMATIC Logon central user management: 6AV2107-0MA00-0AA0 family

8.5 Choose the engineering license

• Single programmer, single seat: SIMATIC WinCC Engineering (basic).
• Floating license in a team: WinCC Engineering Floating License.
• Combo ES+RT: 6AV2100-0AA00-0AA0 family (Engineering included for free with the runtime combo at higher tiers, depending on campaign).

8.6 Order and stage

1. Order through an authorized Siemens distributor (Siemens Industry Mall or local partner).
2. Receive the license certificate by e-mail; the .zip license key is downloaded from the License Portal.
3. Activate on the target IPC/PC before commissioning — not in the middle of a plant acceptance test.

9. Verification and Commissioning Checks

After installation, verify the following before signing off the SCADA:

1. License activation: ALM shows the runtime license as "valid" on the target. WinCC RT starts without the yellow "trial mode" banner.
2. Tag count headroom: In WinCC RT, the diagnostic screen "Runtime → Tools → Statistics" reports the configured power tag count vs. the licensed quota. Margin should be ≥ 20 %.
3. Modbus connection health: Connection status channel in WinCC shows "connected" for each Modbus connection. Verify with a controlled write/read cycle from the WinCC tag simulator.
4. Database / report generation: Trigger a manual report. Confirm the file/SQL row is produced with the correct timestamp and content.
5. Alarm routing: Force an alarm from the PLC, confirm the alarm appears on the screen, is logged to the archive, and triggers the configured e-mail (if option licensed).
6. Power-fail recovery: Hard-reboot the IPC; confirm WinCC RT comes up automatically, re-establishes all Modbus connections within the configured timeout, and replays the alarm log.
7. Backup: Image the IPC, store the project, the license keys, and the ALM report together in a versioned archive.

10. Common Pitfalls and Field Tips

11. Recommended Configuration for the Water-Purification Plant

For the scenario in the field report (1× MicroLogix 1400, ~20 I/O modules, Modbus TCP, 10 report types, single database), the smallest viable bill of materials is:

1. Hardware: SIMATIC IPC227G (or similar) with 15" display variant, Windows IoT Enterprise LTSC 2024.
2. Runtime: WinCC RT Advanced, 2 048 PT (covers the 600-1 000 projected tags with margin).
3. Reporting: Built-in RT Advanced report designer with scheduled PDF output to a network share; CSV log to the same share. (Upgrade to RT Professional + Process Historian + Information Server if multiple operator stations or a web dashboard are required.)
4. Engineering: SIMATIC WinCC (TIA Portal) Engineering, floating or single license, latest version (V18 or V19, as supported by the installed firmware on the panel or IPC).
5. Modbus driver: the TIA Portal "Modbus TCP" plug-in — no separate license.
6. Database sink: optional WinCC/Connectivity Pack if direct SQL Server writes are required from RT Advanced; otherwise export CSV/SQLite and bulk-insert to SQL Server via a Windows scheduled task.

If the system is destined to grow to a second operator desk, a Process Historian, or Information Server web reports, start with RT Professional from the beginning. The price premium is recovered within a year when the first upgrade is needed.

12. Quick Reference: License Decision Matrix

For any non-trivial project, contact an authorized Siemens distributor with the inventory from §8.1 in hand. The dealer's role is to produce a current bill of materials against the current Industry Mall catalog — the rules above will let you evaluate, not replace, that quote.