Connecting SIMATIC KTP900 Basic to LOGO! 8 Controllers: Configuration Guide

A SIMATIC HMI KTP900 Basic (Siemens article number 6AV2123-2JB03-0AX0) can be used as a visualization and operator panel for one to four LOGO! 8 logic modules over PROFINET. This guide explains the supported communication paths, the WinCC Basic V13 (TIA Portal) project structure, the practical limits of direct connection, and how to scale a visualization to more than four LOGO! controllers. The guide also clarifies the role of the LOGO! CMK2000 KNX communication module and the boundary between virtual HMI buttons and physical LOGO! inputs.

1. Hardware Overview

1.1 SIMATIC HMI KTP900 Basic (6AV2123-2JB03-0AX0)

The KTP900 Basic is a 9-inch widescreen basic panel from the SIMATIC HMI portfolio. The relevant specifications for a LOGO! integration project are summarized in the table below.

The official Siemens product page for the KTP900 Basic is available at SIMATIC HMI KTP900 Basic on SiePortal.

1.2 LOGO! 8 Controller Family

LOGO! 8 is the 8th generation of the Siemens logic module. All LOGO! 8 base modules with a part number suffix ...BA8 or ...B0 provide an integrated Ethernet/PROFINET interface. The base modules expose a fixed image of the process variables (inputs, outputs, flags, network inputs/outputs) that can be read and partially written by an HMI panel using the S7 communication protocol. Typical base modules referenced in this integration are:

Verify the exact MLFB and firmware version (currently 1.8x.x at time of writing) on the Siemens LOGO! product support page before starting the project. The set of variables accessible to a PROFINET S7 partner is documented in the LOGO! system manual under the topic "Variable addresses for S7 communication".

2. Communication Architecture

The KTP900 Basic exposes exactly one PROFINET interface, and each LOGO! 8 base module also exposes one PROFINET interface. The two supported integration paths for connecting the panel to LOGO! logic modules are described below.

2.1 Direct Connection (1 to 4 LOGO! Controllers)

The HMI panel can establish up to four independent S7 connections, one per LOGO! base module. All four controllers and the KTP900 must share the same IP subnet and must use PROFINET (Ethernet-based S7 communication) as the transport. No additional gateway, switch, or communication module is required between the panel and the LOGO! modules for a 1-to-4 configuration.

Example topology for a 4-LOGO! direct connection:

A simple unmanaged Ethernet switch (e.g. Siemens SCALANCE XB004-1) or a star topology with individual patch cables into an office-style switch is acceptable. Managed switches with PROFINET conformance class B or higher are recommended when more than four PROFINET devices share the same physical segment.

2.2 Indirect Connection (More than 4 LOGO! Controllers)

When more than four LOGO! base modules must be visualized on a single panel, the recommended pattern is to use one LOGO! as a "data concentrator". The concentrator LOGO! exchanges network variables with the other LOGO! base modules using the LOGO!-to-LOGO! PROFINET network, and the KTP900 only talks to the concentrator. The relevant network limits are summarized in the next section.

3. Connection Limits and Sizing Rules

4. Prerequisites

1. Hardware
   • 1 × SIMATIC HMI KTP900 Basic (6AV2123-2JB03-0AX0)
   • 1–4 × LOGO! 8 base modules with integrated Ethernet (any ...0BA8 or ...B0 series)
   • Standard Cat5e/Cat6 Ethernet cables (crossover is not required on modern switches)
   • Optional: SCALANCE XB004-1 unmanaged switch for star topology
2. Software
   • STEP 7 Basic V13 or TIA Portal V13 (or later) with WinCC Basic installed
   • LOGO! Soft Comfort V8.x for offline program development on the PC
3. Network addressing
   • A single IP subnet, e.g. 192.168.0.0/24
   • KTP900 default IP: 192.168.0.10 (configurable from the Control Panel on the panel)
   • LOGO! 8 default IP: 192.168.0.20 (configurable from the LOGO! onboard display or LOGO! Soft Comfort)
4. User authority: Local administrator on the engineering PC to install TIA Portal and to allow the WinCC Basic V13 runtime to write to the panel's flash.

5. Step-by-Step Configuration

Step 1 — Assign IP addresses to the LOGO! 8 base modules

1. On the LOGO! base module, open the onboard menu: Main menu → Network → IP address.
2. Set the IP address, subnet mask, and (if used) router. For a 4-LOGO! direct project, typical assignments are:
   • LOGO! #1: 192.168.0.20 / 255.255.255.0
   • LOGO! #2: 192.168.0.21 / 255.255.255.0
   • LOGO! #3: 192.168.0.22 / 255.255.255.0
   • LOGO! #4: 192.168.0.23 / 255.255.255.0
3. Repeat for each base. Use a unique IP per device; do not duplicate addresses in the same subnet.

Step 2 — Configure the KTP900 Basic IP address

1. Power the panel, then call up the Control Panel by pressing the Control Panel button on the screen (icon may be hidden; reach it via Start → Settings → Control Panel).
2. Open PROFINET settings and assign IP 192.168.0.10, subnet 255.255.255.0.
3. Set the device name (PROFINET name) to ktp900 or any name compatible with your TIA Portal project.
4. Confirm with Apply and reboot the panel.

Step 3 — Create the TIA Portal project

1. Start TIA Portal V13 (or later) and create a new project: Project → New. Name the project, e.g. LogoHmi_4Cell.
2. In the project tree, choose Add new device → HMI → SIMATIC HMI → KTP900 Basic → 6AV2123-2JB03-0AX0.
3. Add the LOGO! base modules: Add new device → PLC → LOGO! 8 → 6ED1052-1CC08-0BA0 (or your exact part). Repeat for each base. TIA Portal will automatically create a PROFINET subnet.
4. Connect the PROFINET port of the panel with the PROFINET port of each LOGO! by drag-and-drop in the Devices & Networks editor.

Step 4 — Configure the S7 connections

For each LOGO! base module, the HMI must know the IP address and the rack/slot of the LOGO! CPU. The required parameters are summarized below.

Repeat the connection entry until all four S7 connections are listed. After the fourth one, TIA Portal will report that no further S7 connections are available on the panel — this is the visual confirmation of the 4-connection limit.

Step 5 — Create HMI tags and bind them to LOGO! addresses

Each HMI tag must reference an S7 address on the LOGO! that the HMI will read or write. The most commonly used addresses in a LOGO! 8 project are listed in Table 5. The exact byte/bit numbering is documented in the LOGO! 8 system manual under the topic "Process image of inputs/outputs".

To create a tag in WinCC Basic V13, right-click the panel's tag table and select Add new tag. Use the dialog to bind the tag to a specific connection and S7 address, for example:

Name:         Logo1_Input_I1
Connection:   Logo1_S7
Address:      %I0.0  (or IB0 / bit 0)
Acquisition:  Cyclic in operation, 1000 ms
Length:       1 bit

Step 6 — Design screens with virtual operator controls

Drag a "Button" or "Switch" object onto a screen. In its properties, bind the Set bit event to an HMI tag pointing to a LOGO! flag (M) or network output. This produces a virtual touch button on the panel that writes a value to the LOGO! variable image. The LOGO! program must then read that flag and act on it — the HMI does not write directly to a physical LOGO! input.

Example binding for a virtual START button:

Event:        Press
Tag:          Logo1_Start_Virtual
Address:      %M0.0  (flag M1 in LOGO! Soft Comfort)
Mode:         Set bit while pressed
Acknowledge: No

Inside the LOGO! program, add a flag M1 as an input to a function block. The flag can be used as a normal digital signal, for example to set a RS flip-flop that energizes a physical output.

Step 7 — Compile, download, and run

1. Select the HMI in the project tree and click Compile → Software (rebuild all). Resolve any errors reported in the Inspector window.
2. Connect the engineering PC to the panel's PROFINET port and click Download to device → Software. Enter the panel's IP 192.168.0.10.
3. Tick Overwrite all for the first download so the existing project is replaced.
4. Wait for the panel to restart. The startup screen will show your configured start screen.

6. Scaling Beyond 4 LOGO! Controllers

When more than four LOGO! base modules must appear on a single KTP900 screen, the most maintainable topology is a single concentrator LOGO!. The pattern is shown below.

The concentrator LOGO! uses its 8 S7 connection resources to talk to the seven other LOGO! base modules over PROFINET. The 64 network input / 64 network output variables of the LOGO! are used to publish the state of each satellite into a normalized data set on the concentrator. The KTP900 only has to talk to the concentrator (one S7 connection) and reads the consolidated data block. The cycle time penalty is small (one PROFINET round trip of 1–10 ms per satellite).

7. KNX Integration and the CMK2000 Module

The LOGO! CMK2000 (Siemens MLFB 6BK1700-0BA20-0AA0) is a communication module that is clipped onto the left side of a LOGO! 8 base module to give the LOGO! a KNX TP1 interface. Its purpose is solely to allow a LOGO! 8 to act as a KNX device on a KNX bus. It is not a PROFINET gateway and it is not required to connect a LOGO! 8 to a SIMATIC HMI panel. The CMK2000 only becomes relevant when the LOGO! 8 must interwork with KNX-certified building automation devices (e.g. wall switches, blinds actuators, HVAC controllers).

8. Commissioning and Verification

After the project has been compiled and downloaded, run the following verification steps before handing the system over to operations.

1. Connectivity test from the panel
   • On the panel, open Start → Settings → Network and Dial-up Connections → PN_X1 and verify that the link is "Connected" and the speed is 100 Mbit/s full-duplex.
   • Open Start → Programs → Service & Commissioning → Transfer and ping each LOGO! IP in turn. Successful reply confirms the panel-to-LOGO! path.
2. Variable test from a screen
   • On a test screen, place a numeric I/O field bound to a known LOGO! flag (e.g. M1). Toggle M1 from LOGO! Soft Comfort online mode and confirm the value on the panel changes within two update cycles (≤ 4 s with a 2 s poll).
   • Place a button bound to a writable flag (M2). Press the button and verify in LOGO! Soft Comfort online that M2 changes to 1 while the button is held and returns to 0 on release.
3. Error and diagnostic test
   • Disconnect one PROFINET cable. The connection status on the panel should switch to "Disconnected" within the configured diagnostic time (default 3 s). Reconnect and verify automatic reconnection.
   • Check the LOGO! diagnostic buffer (online in LOGO! Soft Comfort) for S7 communication entries.
4. Cycle time check
   • Read the LOGO! cycle time on the onboard display. If the cycle exceeds 50 ms, the project may need to be split across multiple LOGO! modules to keep the HMI responsive.

9. Troubleshooting Matrix

10. Frequently Asked Questions