1. Overview: Why the LOGO! 0BA8 + KTP700 Basic Combo Needs Special Handling
The Siemens LOGO! 230RCE (6ED1052-1FB08-0BA1) from the 0BA8 generation and the SIPAMATIC KTP700 Basic PN HMI panel are both supported by TIA Portal, but they do not interoperate the way a SIMATIC S7-1200 and a Comfort Panel do. The LOGO! does not expose a fully symbolic tag database to TIA Portal, has no concept of data blocks (DBs) from the HMI's perspective, and exposes its real-time data only through three addressable areas:
- I / Q – process image of physical digital inputs and outputs (visible only inside the LOGO! program).
- M – digital markers / flags (bit memory, internal to the LOGO!).
- VM – Variable Memory, the byte/word-addressable area exposed over the S7 communication partner interface. This is the only area the HMI can read or write.
TIA Portal V13 SP1 (the version shipped with the 0BA8 starter bundle) is the first release where the LOGO! 0BA8 base unit appears as a selectable HMI partner in the device catalog. If you are following older Siemens tutorial videos based on TIA Portal V11 or V12, you will see that the LOGO! is not listed as a peer – this is why tutorials that begin with "Add an S7-1200 then add the HMI" do not translate directly to a LOGO!-based system.
The reference architecture for this guide is:
2. Prerequisites
| Item | Version / Part | Notes |
|---|---|---|
| LOGO! base unit | 6ED1052-1FB08-0BA1 (230RCE, 0BA8) | Firmware >= FS:04 recommended |
| LOGO!Soft Comfort | V8.0 / V8.1 / V8.2 | Must match or exceed base unit FS version |
| LOGO! 0BA8 HMI application examples | Siemens Entry-ID 109741136 | Use as project template |
| TIA Portal | V13 SP1 Update 7 or newer (V13 SP2 ideal) | Installs WinCC Basic V13 SP1 |
| HMI panel | 6AV2 123-2GB03-0AX0 (KTP700 Basic, PN, mono) | Image V13.0.1.0 or newer |
| Ethernet cable | Cat5e, <= 100 m | Direct connection is fine, no switch required |
Before opening TIA Portal, install both LOGO!Soft Comfort V8 and TIA Portal V13 SP1. Installing LOGO!Soft Comfort before TIA Portal registers the LOGO! GSDML into the TIA device catalog so the 0BA8 appears under PLC > LOGO! > 0BA8 > LOGO! 230RCE.
3. Configuring the LOGO! Network Interface
Set the IP parameters on the LOGO! on the device itself (not in LOGO!Soft Comfort) before connecting to TIA Portal. From the LOGO! front keypad:
- Navigate to Menu > Network > IP Address.
- Enter an IP address that shares the first three octets of your HMI, e.g.
192.168.0.10 / 255.255.255.0. - Disable the DHCP client (set to Off) – the LOGO! has no DHCP server role.
- Under Network > Subnet Mask, confirm
255.255.255.0.
If you prefer to set the address from LOGO!Soft Comfort, go to Tools > Transfer > Ethernet > Configure Network Interface. The tool pushes the address into the LOGO! over USB or Ethernet.
4. Enabling VM (Variable Memory) Mapping in LOGO!Soft Comfort V8
The Variable Memory is the bridge between your ladder program and the HMI tags. Without enabling VM mapping, the HMI cannot see anything other than I, Q, M, AI, AQ and a few status words.
- Open your ladder project in LOGO!Soft Comfort V8.
- Select File > Properties > VM Mapping (German UI: Datei > Eigenschaften > VM-Zuordnung).
- Tick the Enable VM Mapping checkbox. The dialog displays a 2-column table with 850 byte slots (0…849) for the 0BA8.
- For every internal value you want to expose to the HMI, assign a logical name and a starting VM byte.
| Symbolic Name (your choice) | VM Byte | Data Type | Used For | |
|---|---|---|---|---|
| HMI_CounterPreset | VW0 | WORD | HMI→PLC counter preset (0–999) | |
| HMI_MotorPassCount | VW2 | WORD | Current pass count mirrored to HMI | |
| HMI_StatusWord | VW4 | WORD | Bit-packed machine status | |
| HMI_ScreenSelect | VW6 | WORD | PLC→HMI screen index trigger |
| Tag Name | Plc Address | Data Type | Length | Access |
|---|---|---|---|---|
| HMI_CounterPreset | VW0 | Word | 2 bytes | <-- read/write |
| HMI_MotorPassCount | VW2 | Word | 2 bytes | read only |
| HMI_StatusWord | VW4 | Word | 2 bytes | read only |
| HMI_ScreenSelect | VW6 | Word | 2 bytes | read only |
VW0 directly; the editor will accept the LOGO! naming convention because the connection target is configured as a LOGO! 0BA8. If the dropdown only shows DB-style addresses, your connection partner is wrong – re-check step 5.1.7. Counter Preset From a Symbolic I/O Field (Drop-Down Menu)
The classic pattern: the operator selects a value (e.g. "2 passes", "4 passes", "10 passes") in a drop-down on the HMI. The selection writes an integer into a LOGO! counter's preset (threshold SV).
7.1 HMI Side
- From the Toolbox, drag a Symbolic I/O field onto your screen.
- Configure it as Output/Input (the operator must be able to change it).
- Bind it to the tag
HMI_CounterPreset. - Set Representation = Decimal, range 1–999.
- In the Text list editor, create a list with three entries:
Display Text Value 2 passes 2 4 passes 4 10 passes 10
7.2 LOGO!Soft Comfort Side
LOGO!'s counter blocks do not have an SV input that can be written from the VM area directly. Use an Analog Comparator or an Up/Down Counter block and feed its threshold from a VM-mapped analog flag:
- Place an Up/Down Counter block (function code 011).
- Wire:
- Cnt = the sensor that detects one machine pass.
- Dir = a constant high (count up only).
- R = your machine reset signal.
- Right-click the block and open Block Properties > Parameter. Change On threshold (SV) from a literal value to the symbolic reference
VW0by clicking the small icon next to the field and selecting VM Address > VW0. - LOGO!Soft Comfort now shows "VW0" where the literal "4" used to be. At runtime the LOGO! re-reads the threshold every scan from the VM area.
Wire the counter's output Q to your motor starter coil. Each rising edge on Cnt increments Cnt; when Cnt >= VW0 the output trips, and the next Cnt edge resets Cnt because the LOGO! Up/Down counter rolls over automatically once the threshold is exceeded – alternatively use a separate reset pulse from the same output.
8. Driving HMI Screen Change From a LOGO! Output
You can absolutely use a LOGO! output to navigate the HMI. There are two supported techniques.
8.1 Area Pointer Technique (recommended)
- In the HMI project tree, open Connections > S7 connection_1 > Area Pointers.
- Enable Screen number (Job mailbox 51, length 4). The HMI allocates the pointer
VW100on the LOGO! by default – remember this address. - For each screen you want to trigger, add a numeric constant ladder branch in LOGO!Soft Comfort that writes the screen number into
VW100, then triggers a 1-cycle pulse to force the HMI to re-read it. The standard pattern uses an Analog Flag whose input is tied to a constant:
--[ I1 (Request screen 4) ]--[ Constant 4 ]--> AnalogFlag ref=VW100
\
--[ I2 (Request screen 5) ]--[ Constant 5 ]--> AnalogFlag ref=VW100Because LOGO!Soft Comfort blocks cannot generate an unconditional := 4 statement, build the constant with an Analog Multiplexer or Math block whose input is a digital flag and whose value is the screen number.
8.2 Scheduler / Event Technique
- On the HMI, open Scheduler > Add task > Event-driven.
- Use a tag-based trigger: when the LOGO! writes a non-zero value to VW6, the HMI executes ActivateScreen("Screen_" + VM_word_value, 0).
- This decouples the screen index from the LOGO! and lets you choose any naming convention. Trade-off: requires screen names to follow the chosen convention.
9. Compilation, Download, and First Power-On
- In LOGO!Soft Comfort: Tools > Transfer > PC → LOGO!. Send the program over Ethernet (requires the LOGO! IP to be reachable).
- In TIA Portal: LOGO!_1 > Compile > Download to device. Use the same IP
192.168.0.10in the search. - Compile the HMI project: right-click HMI_1 > Compile > Software (rebuild all).
- Download the HMI image: HMI_1 > Download to device > Software (incl. images and recipes). Accept the image overwrite prompt.
- Power-cycle the LOGO!. Wait until the LED on the Ethernet port shows solid green (S7 connection established).
10. Verification Checklist
| Step | Expected Result | Pass / Fail Indicator |
|---|---|---|
| LOGO! ping from HMI | Reply from 192.168.0.10 in < 5 ms | Use WinCC "Tools > Online > Ping" |
| LOGO! diagnostic page (Display) | Status page lists the HMI as connected partner | Front-keypad menu: Diagnostics > Connection |
| Tag monitor on HMI side | HMI_CounterPreset shows 0 at idle | TIA Portal online → HMI Tags → "Monitor all" |
| Set VM0 to 5 from HMI | LOGO! Up/Down counter threshold reads 5 | LOGO! display: counter block > SV = 5 |
| Trigger Q4 from ladder | HMI jumps to screen 4 within 500 ms | Visible transition |
| End-to-end pass count test | Select "4 passes", trigger 4 sensor edges, motor stops on 5th edge | Functional test |
11. Troubleshooting Matrix
| Symptom | Likely Root Cause | Fix |
|---|---|---|
| HMI shows "Connection failed" | Wrong IP / subnet mismatch | Re-confirm both nodes share first 3 octets; disable PC firewall temporarily |
| TIA Portal shows "Address VW0 not valid for this partner" | Connection partner is configured as S7-300/400 instead of LOGO! | Re-create the S7 connection; select LOGO!_1 as the partner, not "unspecified" |
| Counter ignores HMI value | VM mapping not enabled in LOGO!Soft Comfort properties | Re-check File > Properties > VM Mapping; recompile and re-download to LOGO! |
| HMI writes 5, LOGO! reads garbage (e.g. 32768) | Word alignment / byte-order mismatch (little-endian vs big-endian) | LOGO! 0BA8 is little-endian; TIA Portal default matches. Check no manual swap box was ticked |
| Screen does not change on Q4 | Area pointer "Screen number" disabled | Connections > Area Pointers > enable Screen number pointer at VW100 |
| Slow updates (> 2 s) | Acquisition cycle set to 2 s instead of 100 ms on the HMI tag | HMI tag properties > Acquisition cycle > 100 ms |
| LOGO! Soft Comfort reports "Online connection lost" mid-transfer | LOGO! entered STOP due to error | Read LOGO! display for error code; cycle power after clear |
| Drop-down list shows 0 always | Text list value type mismatch | Text list entries must be Integer, not DINT |
12. Common Pitfalls From The Field
- Confusion between M flags and VM. Many tutorials imply that M0.1, M0.2 are accessible from the HMI. They are not – M flags are internal to the LOGO! and the HMI cannot poll them through S7. Use VM, not M, for any HMI-bound data.
- Counting from 1 vs 0. LOGO!'s Up/Down counter starts at 0 and trips on the edge after SV is reached. If you preset 4, the output energizes on the 5th edge. Many "off-by-one" reports stem from this behaviour – decide whether the operator wants "4 passes" to mean "4 edges to completion" or "output pulses 4 times" and adjust accordingly.
- Forgetting to re-download after changing VM mapping. LOGO!Soft Comfort V8 caches the VM mapping in the project. TIA Portal is unaware of it. Always recompile in LOGO!Soft Comfort, then run a full download to the LOGO! before testing the HMI.
- Using the KTP700 Basic DP. The DP variant (6AV2 123-2GA03-0AX0) only supports PROFIBUS and cannot reach the LOGO! over PROFINET. Confirm the part number on the rear label.
- LOGO! in RUN with cyclic STOP. If the LOGO! firmware is < FS:04 the VM area is read-only. Update to at least FS:04 before relying on VM writes from the HMI. The current firmware is downloadable from the Siemens support portal (Entry ID 109741136).
13. Related Siemens Resources
For deeper reference, the official Siemens documentation for the LOGO! 0BA8 base unit is the LOGO! System Manual, 06/2014 edition (A5E00119041-04). It covers the VM area, S7 communication, and the diagnostic page. Application examples with HMI integration are bundled in the LOGO!Soft Comfort V8 installer under Examples > HMI. The TIA Portal V13 SP1 help system (F1 inside TIA Portal) contains the "Configuring a LOGO! Connection" section that walks through the same steps with screenshots.
Can the KTP700 Basic read LOGO! marker bits (M0.1, M0.2, ...)?
No. The S7 partner interface of the LOGO! 0BA8 only exposes I, Q, AI, AQ and the VM area to a client. Marker bits are internal to the LOGO! and cannot be polled over the network. Use VM words or VM bits instead – for example map M0.1 to a free VM bit inside your ladder and read VMxy from the HMI.
What is the difference between VM and M in the LOGO! 0BA8?
VM (Variable Memory) is the byte/word-addressable area exposed over Ethernet and is the only memory the HMI can read or write. M (markers/flags) are bit-addressable internal relays. M flags cannot be reached from TIA Portal at all; they are only available inside the LOGO! program itself.
Why does TIA Portal V13 SP1 not show the LOGO! 0BA8 as a device option?
The LOGO! 0BA8 device description ships with LOGO!Soft Comfort V8. If TIA Portal was installed before LOGO!Soft Comfort, the GSDML/HSP is missing. Reinstall LOGO!Soft Comfort V8 with administrator rights, then restart TIA Portal and run "Update HSP" from the TIA Portal options menu.
Can the LOGO! 0BA8 trigger an HMI screen change from a digital output (Q4)?
Yes, but only via the Area Pointer "Screen number" or via a Scheduler task on the HMI that reads a VM word you set from the LOGO!. Direct "Q4 → screen 4" wiring does not exist – you must place a constant on the VM word, and the HMI polls it.
What is the maximum VM size on a LOGO! 0BA8?
850 bytes (VW0 to VW849). Bytes 0–7 are partially reserved by the LOGO! system for diagnostics; in practice start at VW8 to avoid collisions. Each WORD occupies 2 bytes, each DWORD 4 bytes, so the maximum number of WORD tags is roughly 420.
Why does my counter ignore the HMI selection and always run with the original preset?
The block's threshold (SV) field must reference the VM word (VW0), not a literal number. In LOGO!Soft Comfort open the counter's block properties, click the icon next to the SV field, and choose "VM Address" instead of "Constant". Then recompile and re-download the LOGO! program.
Does the KTP700 Basic support PROFINET IRT for the LOGO! 0BA8?
No. The LOGO! 0BA8 only supports PROFINET RT (real-time, non-IRT). The KTP700 Basic PN also only supports RT, so the two are compatible. Configure the PROFINET interface as "RT" in the device properties; leave IRT options unchecked.