Controlling Siemens LOGO! 0BA7 with iPhone or iPad: Complete Technical Reference

The Siemens LOGO! 0BA7 logic module (released 2011 as part of the LOGO! 6 generation) is one of the most widely deployed micro-PLCs in small-machine and building-services automation. Because it ships with a built-in Ethernet interface on the LOGO! 6ED1052-xxx06-0BA7 variants, the controller is theoretically addressable from any device that runs an HTML5 browser or an S7 client — including the Apple iPhone and iPad families. This reference consolidates every documented pathway for iOS-based control of an OBA7, including the LOGO! web server, the LOGO!Monitor PC-relay method, mySCADA HMI, and direct S7 communication, and provides the network, firmware, and configuration prerequisites required for a stable field installation.

1. LOGO! 0BA7 Hardware and Communication Interfaces

The 0BA7 generation (ordering prefix 6ED1 052-1xxxx-0BA6 for the base module and 6ED1 055-1xxxx-0BA6 for the pure relay variants) introduced the integrated RJ45 Ethernet port on the LOGO! …CE device families. The following catalog numbers are the typical 0BA7 Ethernet-capable devices encountered in the field:

For the older 0BA6 generation (without integrated Ethernet), the communication expansion module 6ED1055-5MC00-0BA0 (CM EIP/KOP) is required to obtain an Ethernet port. In all 0BA7 and 0BA6-with-CM configurations, the integrated interface exposes a fixed IP fallback (192.168.0.10 on the BM) plus user-configurable IP parameters accessible through LOGO! Soft Comfort V8.0 or later, or directly from the device menu.

The 0BA7 also retains the legacy RS-232 service port available through the LOGO! PC cable (6ED1057-1AA00-0BA0). This is the path required for the Bluetooth-to-RS232 adapter workaround discussed later in this reference.

2. Built-in Web Server Capability

Starting with LOGO! Soft Comfort V7.0, Siemens enabled the on-board web server of the 0BA7. When a circuit program is loaded into the BM, the user can mark variables (I, Q, M, network inputs, analog thresholds) for visibility and assign text labels through the Tools → Define Web Server Variables… menu in LOGO! Soft Comfort. Once compiled, the LOGO! 0BA7 will host a small HTTP server on TCP port 80 that serves an HMI-style page plus an XML status interface.

The web server supports three interaction modes:

• Read-only monitoring — current state of every selected input, output, flag, and analog value.
• Web-based control — if the program is configured with web operator rights, the user can toggle a maximum of 16 web variables (4 inputs + 4 outputs + 8 memory flags, by firmware allocation) from the browser.
• Status XML / JSON — for direct polling from third-party iOS clients, the URL http://<logo-ip>/logo.xml returns a live snapshot.

The web server is fully HTML5 compliant; no Java plug-in, ActiveX control, or Adobe Flash is required. This is the foundational reason an iPhone or iPad can interact with the controller without installing any vendor-specific app — the mobile Safari / Chrome engine renders the LOGO! generated page directly.

3. Native iOS Browser Access — Step-by-Step Configuration

This is the simplest and least expensive method, and uses only the Apple-supplied mobile browser. Use the procedure below to bring the LOGO! 0BA7 onto the same network as the iPhone/iPad and access it through Safari or Chrome.

3.1 Prerequisites

• LOGO! 0BA7 BM with catalog suffix …CE (or 0BA6 BM + CM EIP expansion).
• LOGO! Soft Comfort V7.0+ installed on a Windows PC with Ethernet.
• Standard Cat-5/6 patch cable (crossover not required on modern 0BA7 — Auto-MDI/MDIX is supported).
• iPhone or iPad running iOS 12 or later. iOS 13 introduced Voice Control which can be useful for hands-free interaction with the LOGO! HMI page; iOS 13+ also brought HTTPS- and TLS-related hardening relevant to the 0BA7 web server configuration.
• DHCP server on the local network, or a manually assigned static IP within the same subnet as the BM.

3.2 Configure the LOGO! 0BA7 IP Parameters

1. Power up the BM and press ESC + OK to enter the setup menu. Navigate to Network → IP Address.
2. Enter a static address, e.g. 192.168.1.50, subnet mask 255.255.255.0, and gateway 192.168.1.1. Siemens recommends reserving the address in the DHCP server to prevent address conflicts.
3. Set the Web server parameter to ON.
4. Define a Web User password if you intend to use the control (write) functions. Default is no password (read-only).
5. Save and restart the BM.

3.3 Define the Web Variables in LOGO! Soft Comfort

1. Open the project in LOGO! Soft Comfort.
2. Choose Tools → Define Web Server Variables (Ctrl+W in classic UI).
3. For every I/O, flag, or analog block you want to expose, click Add. Assign a label string (UTF-8, max 32 chars) and a display color.
4. If write access is needed, enable the Operator checkbox on the respective variable. Note: enabling operator rights on more than the maximum number of writable web variables is silently ignored by the firmware.
5. Save the project and download the program to the BM via Ethernet or the LOGO! PC cable.

3.4 Connect the iPhone or iPad

1. Join the iPhone/iPad to the same Wi-Fi SSID as the LOGO! 0BA7. Confirm by opening Settings → Wi-Fi and reading the assigned address. If the SSID has no internet uplink, the device will still operate in local mode — useful for isolated control panels.
2. From the iOS Home screen, open Control Center (swipe down on the top-right) to verify Wi-Fi connectivity. Open Safari.
3. Type the LOGO! IP address, e.g. http://192.168.1.50, into the URL bar.
4. The LOGO! default web HMI appears. Tap any operator-enabled variable to toggle its state. The page auto-refreshes every 5 seconds (firmware default, configurable through refresh_ms in the web configuration block, range 1000–60000 ms).

3.5 Add the Page to the iOS Home Screen

For a kiosk-style permanent deployment, save the LOGO! HMI URL to the iOS home screen:

1. In Safari, tap the Share icon (square with up arrow).
2. Choose Add to Home Screen. Name it (e.g. Pump Station).
3. Tap Add. The LOGO! web page will open full-screen, hiding Safari's address bar, providing a near-native HMI experience.

4. LOGO!Monitor PC-Relay Method

For users who already have a permanently running PC in the plant and want to leverage the richer LOGO!Monitor visualization, the iOS device can connect through a remote-desktop or VNC bridge. The PC runs LOGO!Monitor (delivered with LOGO! Soft Comfort) and the iPhone/iPad connects via a remote-desktop client such as Microsoft Remote Desktop, Chrome Remote Desktop, Splashtop, or Jump Desktop.

4.1 Why Choose this Method

• LOGO!Monitor provides more sophisticated graphics than the on-board web server, including trend charts (up to 4 simultaneous) and animated symbols.
• The PC can log historical data to a CSV/SQL backend while the iOS device is used for ad-hoc operator interaction.
• Multiple iOS clients can connect concurrently to the same PC without exceeding the LOGO! 0BA7's single TCP-connection limit (only one S7 connection is supported by the firmware — additional polling clients must be multiplexed through the PC).

4.2 Configuration Steps

1. Install LOGO! Soft Comfort (V7.0+ recommended for 0BA7) and ensure LOGO!Monitor is present in the installation.
2. Connect the PC to the LOGO! 0BA7 via Ethernet. In LOGO!Monitor, configure the Ethernet interface: Settings → Interface → Ethernet (TCP/IP). Enter the LOGO! IP address.
3. Create a project file (.lma) with the desired trend curves, text, and operator buttons.
4. Install a remote-desktop tool on the iOS device. Microsoft Remote Desktop is free from the App Store and supports Gateway connections. Chrome Remote Desktop is also free and platform-agnostic.
5. Configure the PC firewall to allow the chosen remote-desktop protocol. Common ports: RDP 3389, VNC 5900, Chrome Remote Desktop 443 (HTTPS out).
6. From the iOS device, open the remote-desktop app, connect to the PC, and operate LOGO!Monitor. Because the LOGO! HMI runs at native PC resolution, the iOS app can be set to scale-to-fit, with pinch-zoom for fine motor control.

5. mySCADA and Third-Party HMI Solutions

For complex iOS HMI projects, the mySCADA Editor and mySCADA Pro suite (referenced by the original poster as a candidate solution) is one of the few platforms with first-class iPhone/iPad targeting and direct Siemens LOGO! S7 protocol support.

5.1 mySCADA Architecture

mySCADA uses a two-tier model:

1. mySCADA Designer (Windows / macOS) — drag-and-drop HMI editor that compiles a project into a runnable artefact.
2. mySCADA Pro / mySCADA Mobile (iOS / Android / Windows runtime) — interprets the compiled project and exchanges data with the PLC using S7comm (ISO-on-TCP, port 102) or Modbus TCP (port 502).

For the LOGO! 0BA7, the S7 communication driver is used. The LOGO! firmware implements a subset of the S7-200 PPI-derived protocol, accessible on TCP port 102 of the BM's IP address.

5.2 Adding the LOGO! 0BA7 in mySCADA Designer

1. Launch mySCADA Designer. Choose Project → New and select Siemens LOGO! as the target device family.
2. In the Drivers tab, add a new S7 driver. Configure: IP = LOGO! address (e.g. 192.168.1.50), Port = 102, Rack = 0, Slot = 1 (LOGO! S7 mapping default).
3. Import the LOGO! variable list. mySCADA can read the LOGO! Soft Comfort project file (.lsc / .lsp) and auto-generate tag mappings. The default address ranges are:
   • Digital Inputs: DB 1, byte 0..7 (I1–I8 / I9–I16 with expansion)
   • Digital Outputs: DB 1, byte 8..15 (Q1–Q4 / Q5–Q8 with expansion)
   • Flags: DB 1, byte 16..47 (M1–M27, plus shift-register bits)
   • Analog inputs: DB 1, word 100..115 (AI1–AI8)
   • Analog outputs: DB 1, word 116..123 (AQ1–AQ4)
4. Design the HMI screens with mySCADA widgets (buttons, gauges, trends, alarms). Save and export to .mpr format.
5. Install mySCADA Pro from the App Store on the iPhone/iPad. Open the project from a shared cloud folder (Dropbox, iCloud, OneDrive) or via Wi-Fi file share.
6. Tap the project; the runtime connects to the LOGO! 0BA7 and renders the HMI with full touch interaction, multi-touch gestures, and pinch-zoom.

6. Direct S7 Protocol Apps for iOS

Several iOS App Store applications implement a bare S7comm client specifically for the LOGO! 0BA7 / 0BA8 / 0BA8.3 family. They are typically used by commissioning engineers for diagnostics rather than for permanent operator panels.

For an engineering-grade S7 client, the most common technique is to use a generic ISO-on-TCP client app and manually map each variable to the address ranges shown in Section 5.2. The connection handshake is:

The 0BA7 firmware does not require TSL100-style secure communication, but it does enforce a single S7 connection at a time. Attempting to open a second connection while the first is still active will result in the second client receiving a TPKT RST. This is a common source of "intermittent" connection failures when multiple apps are run in sequence.

7. Bluetooth-to-RS232 Bridge on 0BA6 vs 0BA7

The original forum discussion raises a Bluetooth-to-RS232 converter as a possible solution. This is technically valid only for the older 0BA6 base modules (6ED1 052-1xxxx-0BA0 through 0BA4) that ship with a built-in RS-232 service port on the side of the BM. The Bluetooth converter of choice is the SENA Parani-SD1000 (or equivalent SPP-profile adapter) configured to 9600 8N1 to match the LOGO! PC cable parameters.

The 0BA7 does not have a native RS-232 port; the LOGO! PC cable (6ED1057-1AA00-0BA0) is the only RS-232 path, and it is intended for engineering access, not for runtime control. Attempting to drive a 0BA7 over Bluetooth via the LOGO! PC cable will only allow you to upload/download programs, not to operate the HMI.

For new installations, use the Ethernet pathway described in Section 3 — it is faster, more reliable, and supported on every iOS device since the iPhone 3GS.

8. Network Topology and Security Recommendations

For a plant or building-services deployment, the following topology is recommended:

8.1 Hardening Checklist

• Disable unused services on the LOGO! 0BA7: if remote S7 write access is not needed, set the BM's web user password and keep the S7 write protection bit enabled.
• VLAN separation: keep the LOGO! on a dedicated VLAN with no default route to the corporate LAN. Block inter-VLAN TCP/102 access at the L3 switch.
• Firewall the iOS device: install a mobile device management (MDM) profile to enforce minimum iOS version (iOS 13+ recommended per Apple's Voice Control and security baseline).
• TLS / HTTPS: the on-board web server of the 0BA7 does not support HTTPS. If the SSID is shared with non-control devices, consider routing through a VPN or a reverse-proxy with TLS termination.
• Physical security: iOS devices are easily misplaced. Use Apple Business Manager / Apple School Manager to enable Activation Lock and remote wipe.

9. Comparison of iOS Control Methods

10. Troubleshooting Common Connection Issues

11. Field Commissioning Procedure

Use the following checklist on first-time deployment of an iOS control solution for a 0BA7.

1. Verify 0BA7 catalog number ends in CE (Ethernet variant). Update firmware to the latest service pack via LOGO! Soft Comfort (refer to the Siemens product support page for the current revision).
2. Connect a Windows engineering PC directly to the LOGO! BM with a Cat-6 cable. Open LOGO! Soft Comfort, choose PC → Connect, and verify a successful online session.
3. In Tools → Define Web Server Variables, expose the I/O points of interest. Save and download.
4. Open a desktop browser, navigate to http://192.168.1.50, and confirm that the page renders and that toggle buttons work.
5. Join the iPhone/iPad to the same VLAN, open Safari, and verify the same URL. Tap the Share → Add to Home Screen action.
6. If mySCADA is in scope, install the Designer, import the LOGO! variables, and deploy the project to the iOS device.
7. Document the IP, VLAN, web user password, and refresh interval in the plant asset register. Apply iOS MDM profile if part of a managed deployment.
8. Perform a power-cycle test: remove BM power, restore, confirm the iOS device reconnects within one polling interval.

12. Frequently Asked Questions