Siemens LOGO! 0BA8 Web Server: Monitoring I/O and Variables

Overview: Web Access on LOGO! 6ED1052-1MD00-0BA8

The Siemens LOGO! 8 base module 6ED1052-1MD00-0BA8 is part of the original LOGO! 8 generation (order suffix 0BA8, firmware release 2014). Despite being marketed as the entry-level model, every LOGO! 8 base module with an integrated Ethernet port ships with a built-in HTTP web server. This web server mirrors the LOGO! onboard display (or the optional LOGO! TDE external text display) and is sufficient for remote status observation of a heat-pump control loop, including digital inputs, digital outputs, analog values, flags, and operator message texts.

This article covers what is achievable with the original 0BA8 web server, what is not achievable without upgrading firmware to LOGO! 8.2 (0BA8.2) or higher, how to configure the network connection, enable message-text visibility on the web server, and how to use the LOGO! App for both Android and iOS as an alternative client.

Identifying the Hardware: 6ED1052-1MD00-0BA8

Decode the catalog (MLFB) number before commissioning:

The module exposes one RJ45 Ethernet port on the bottom face. Default IP address from the factory is 192.168.0.200, default subnet mask 255.255.255.0, no default gateway, no DHCP client active.

LOGO! 0BA8 Web Server Architecture

Three logical pages are served by the integrated HTTP daemon on TCP/80:

1. LOGO! Display — duplicates the 6-line, 16-character LCD that the LOGO! base module shows in RUN mode.
2. TDE Mirror — duplicates an attached LOGO! TDE (6ED1055-4MH00-0BA0), if one is connected. Cursor keys (up/down/left/right) and the four function keys (F1-F4) become HTML buttons in the browser view.
3. LOGO! BM (Base Module) Status — diagnostic page with the device order number, firmware version, MAC address, IP configuration, and SD-card status.

The web server refreshes the HTML frames at 1 Hz by default, so the displayed I/O and variable state is essentially real-time for HVAC-class processes (heat-pump setpoint, flow temperature, outside temperature, compressor run bit).

Standard vs Extended Web Server

The user's 6ED1052-1MD00-0BA8 is fixed at the standard web server. To obtain the extended web server, the hardware article number itself must change to a 0BA8.2 or 0BA8.3 module (suffix -0BA1 or higher).

Prerequisites

• LOGO! 6ED1052-1MD00-0BA8 powered with 12/24 V DC on terminals L+ / M.
• Ethernet patch cable to a 10/100 Mbit switch or directly to a PC.
• LOGO! Soft Comfort V8.0 or later (for editing and downloading the program). Available from Siemens Industry Online Support.
• PC or Android phone on the same subnet (192.168.0.x with mask 255.255.255.0).
• For mobile: LOGO! App on Google Play or the iOS equivalent.

Step-by-Step: Enabling Web Server Access

Step 1 — Configure IP Address

1. On the LOGO! onboard display, press ESC until the main menu appears.
2. Navigate to Network and confirm with OK.
3. Set IP Address to a value reachable from your LAN (example: 192.168.0.200).
4. Set Subnet Mask to 255.255.255.0.
5. Set Gateway to your router IP (example: 192.168.0.1) — required if the LOGO! App must reach the LOGO! across the Internet via port forwarding.
6. Confirm and exit.

Alternative configuration: open Tools → Ethernet → Configure in LOGO! Soft Comfort and transfer the IP block via online connection (PC must be on the same subnet temporarily).

Step 2 — Enable Access Protection Settings

1. In the LOGO! menu tree go to Options → Access Protection.
2. Enable the slider Webserver Access. The original 0BA8 firmware does not password-protect the standard web server; only parameter-modification rights are limited to read-only by default.
3. Save with OK.

Step 3 — Configure Message Texts for Webserver Visibility

This is the critical step most newcomers miss. A message text programmed in the FBD circuit diagram does NOT appear on the web server unless its visibility flag is set correctly. In LOGO! Soft Comfort:

1. Open the message text block (function block list → Message Texts).
2. Open the block properties dialog.
3. In the Display On group, check both Both and Webserver. The two checkboxes are independent and both must be ticked for the message to render in the browser.
4. Reference the variables and I/O points you want to expose. Example for a heat-pump application:

Heat Pump Status
Mode:           <Q1>  (Compressor)
Flow temp:      <AM1> °C
Outside temp:   <AM2> °C
Setpoint:       <AM3> °C
Error flag:     <M1>

Symbol mapping:

Step 4 — Verify from Browser

1. On a PC on the same subnet, open a browser and navigate to http://192.168.0.200.
2. The default frame shows the LOGO! display content. The active message text rotates here.
3. If the page returns 404 Not Found, check that Access Protection → Webserver Access is enabled.
4. To reach the device across the Internet, configure NAT/port-forwarding on your router (TCP port 80 to 192.168.0.200) and use the public IP or DDNS hostname. For dynamic IPs, register with a DDNS provider such as DynDNS or No-IP and use the LOGO! Cloud Connector (only available on 0BA8.3+).

Monitoring Inputs, Outputs, and Variables

On the standard 0BA8 web server, the only way to surface a real-time I/O or variable value is to embed it inside a message text. The web server then renders the message text inline in its main frame. Practical workflow for a heat-pump controller:

1. Program two or three message text blocks, each activated by a different flag bit. Stagger them in time so they cycle through the active window without operator scrolling.
2. Embed the variables as <AMx> or <Qx> placeholders.
3. Tick Webserver for each text. The display then updates each second as the program re-evaluates the text and the web server polls the LOGO!.

Direct browsing of an I/O map (a tabulated view of all I/Os like the LOGO! Soft Comfort online view) is not available on the standard 0BA8 web server. The LOGO! Soft Comfort online test can show this tabulated view from a PC, but it requires USB or Ethernet and is not browser-based.

Parameter Modification via Web (Teleservice Equivalent)

The standard 0BA8 web server does not expose arbitrary writeable HTML widgets. Two methods achieve parameter modification:

1. TDE cursor / F-key buttons: The web server exposes the same key widgets that the LOGO! TDE exposes. A flag bit programmed in the FBD circuit diagram (Function Keys block) can be used to toggle AM3 (room setpoint) up or down. The browser user clicks the F-key widget and the value updates. This is the closest you get to "teleservice" on 0BA8.
2. LOGO! App: The Android/iOS app surfaces a TDE-like screen with touch keys and a message-text view. Pressing the touch keys triggers the same F-key flag bits in the FBD, which can be wired to increment or decrement analog memory through an analog arithmetic block.

LOGO! App Setup

1. Install LOGO! App from Google Play (Android) or the App Store (iOS).
2. On the app home screen, tap Add and enter the LOGO! IP address (192.168.0.200) and the optional name.
3. Tap Connect. The app then mirrors the LOGO! display with a touch interface and a numeric/analog panel at the bottom.
4. For remote access across the Internet, use the public IP or DDNS hostname of your router together with the configured port forwarding. The app supports HTTP basic auth (only if a password was assigned in LOGO! → Options → Password).

The LOGO! App is the most user-friendly way to monitor and adjust a heat-pump control from a phone. It uses the same TCP/80 channel as the web server and adds the touch-key virtualization that the standard web server pages also expose for F-keys.

Variable Monitoring Limitations and Workarounds

Verification Checklist

• http://<LOGO_IP>/ returns the LOGO! mirror page in a browser.
• The mirrored display updates at least once per second.
• Each message text block has both Both and Webserver checked.
• F-key flags configured in the FBD respond to the on-screen F-key buttons in the browser.
• LOGO! App connects from the same LAN and shows the same display.
• Mobile browser (Android Chrome, iOS Safari) also renders the display correctly.

Troubleshooting Matrix

Field-Proven Tips

• Document each message-text block's purpose in a comment. The web server shows the text but not the originating block address, which makes diagnostics harder on legacy systems.
• Use clear English or local-language strings. The web server renders the same character set as the LOGO! display, with no UTF-8 fallback for non-Western European characters.
• Lock the LOGO! IP to a static DHCP reservation on the LAN router so the LOGO! App can re-discover it without manual IP edits.
• If the heat-pump cabin is far from the LAN router, consider a 4G industrial router with VPN termination instead of plain port-forwarding, to avoid exposing TCP/80 publicly.

Frequently Asked Questions