Connecting Siemens LOGO! 0BA8 to InTouch via DASSIDirect

Overview: LOGO! 0BA8 to InTouch Integration

Siemens LOGO! 0BA8 — the Ethernet-equipped LOGO! 8 generation (including 0BA8 Standard, 0BA8.S, and 0BA8.FS:05) — exposes its internal I/O, network I/O, markers, and variable memory to S7-compatible clients over its on-board RJ45 port using a subset of the S7-200 communication profile. AVEVA InTouch HMI does not ship a native Siemens S7-200 driver, so the standard, vendor-supported path is to insert Wonderware DASSIDirect (DAServer Direct) with its S7CP_200 device group as the protocol bridge between the LOGO! CPU and the InTouch access name. This article documents the complete configuration: IP addressing, the S7 client/server connection in LOGO! Soft Comfort, TSAP pairing, the S7CP_200 topic in the DAServer Manager, and the InTouch tag dictionary mapping.

The integration is unidirectional or bidirectional over a single TCP session on port 102 (ISO-on-TCP / RFC 1006). DASSIDirect acts as the S7 client, the LOGO! 0BA8 acts as the S7 server, and InTouch reads or writes through the DASServer using a simple, S7-200-style item name syntax (for example VX0.0 for the first network-output bit and VW0 for the first variable-memory word). No OPC tunnel, no KEPware, and no S7-net/PPI adapter is required.

Architecture and Protocol Foundation

LOGO! 0BA8 implements the S7-200 communication subset on top of ISO-on-TCP (TCP/102). The S7 communication model uses a Transport Service Access Point (TSAP) — a two-byte identifier that pairs the local resource of the server with the local resource of the client. For the LOGO! 0BA8, the default local TSAP is 01.00. The DASSIDirect S7CP_200 object is a slot-0 / rack-0 client that mirrors the TSAP pair, opens a TCP connection to the LOGO!, and then performs S7 read/write PDUs at the configured poll interval.

The integration is composed of three layers:

1. LOGO! 0BA8 base module with on-board Ethernet (firmware ≥ 0BA8.Standard ES:02) configured as an S7 server.
2. Wonderware DASSIDirect (DAServer) running as a Windows service, with one S7CP_200 device object (topic) per physical LOGO!.
3. AVEVA InTouch with an Access Name pointing to the DASSIDirect application and the topic name as defined in step 2.

Prerequisites

Step 1: LOGO! 0BA8 Ethernet and S7 Connection Configuration

1. Set a static IP on the LOGO!. The factory default is 192.168.0.10/24. In LOGO! Soft Comfort go to Tools → Ethernet → IP Address and assign an address on the SCADA subnet (e.g. 192.168.0.10, subnet 255.255.255.0, gateway 192.168.0.1). Confirm with a ping from the SCADA PC.
2. Enable the S7 connection. In the same Tools → Ethernet menu, open the S7 Connection dialog. The LOGO! side is the server; you only declare the partner:

3. Compile and download the program. Use PC → Logo! transfer over the same Ethernet cable. If the on-board LOGO! display shows "STOP", switch to RUN after the download completes.
4. Verify the connection is listening. From the SCADA PC run Test-NetConnection 192.168.0.10 -Port 102 (PowerShell) or nc -vz 192.168.0.10 102 (Linux). The TCP handshake must succeed before continuing.

Step 2: DASSIDirect Server Configuration (S7CP_200)

Open the DAServer Manager from the Wonderware program group. The console shows a tree with Configuration at the top and the registered device groups beneath it.

1. Create the device object. Right-click Configuration → Add S7CP_200 Object. Rename it to match the physical asset (e.g. LOGO_0BA8_01). This string becomes the InTouch topic name.
2. Configure the S7CP_200 parameters. Open the new object and fill the Device Properties dialog:

3. Activate the device object. Right-click the S7CP_200 entry and select Start. The status icon turns green within 5–10 seconds once the S7 connection is established. Hover the icon to see the negotiated PDU size and last read timestamp.
4. Test from the DAServer Manager. Right-click the device → Quick Browser → read a known item, for example VX0.0. A successful read returns the current network-output bit value; a failed read returns an error code (see troubleshooting matrix).

Step 3: InTouch Access Name and Tag Dictionary

1. Open WindowMaker as a user with write access to the InTouch application directory.
2. Create the Access Name. Open Special → Access Names → Add:

3. Build the tag dictionary. Open Special → Tagname Dictionary → New and add discrete and analog tags using the DASSIDirect S7-200 item name format. Examples for the standard read/write points:

4. Save and reload. Save the dictionary, close WindowMaker, and restart the InTouch Viewer. The DASSIDirect connection should reach Established state within two poll cycles.
5. Smoke-test on a window. Drop a discrete value display bound to logo_in1_0 and a button toggling logo_nq0_0 on a test window. The InTouch Debugger (Ctrl+Y) confirms read/write activity against the DASSIDirect log pane.

Address Mapping Reference Table

The number of accessible I and Q bytes depends on the LOGO! 0BA8 base module plus any attached digital or analog expansion modules. The maximum VM area address range is firmware-dependent; the 0BA8.Standard firmware (ES:02 and later) typically exposes up to VW850.

Verification

1. Connection state. Open the DAServer Manager → expand the S7CP_200 device → check the status icon. It must be green and the "Last Read" timestamp must be within the poll interval.
2. Tag quality in InTouch. Open InTouch Viewer and the SMC Debugger. All I/O tags bound to the DASSIDirect access name should report quality = Good (192). A Bad quality value (0) indicates a TSAP or IP mismatch, a firewall block, or a stopped S7CP_200 object.
3. Online program view. In LOGO! Soft Comfort connect online, force a network input (NI1) and confirm the corresponding InTouch tag updates within one poll cycle (default 1 s).
4. Round-trip write test. Bind a momentary pushbutton to logo_nq0_0. Press the button; the NQ1 LED on the LOGO! (or the corresponding bit in the online view) must turn on within the poll interval. Release the button; the bit must clear.
5. Log review. Inspect the DASSIDirect log (default path: %SystemDrive%\ProgramData\Wonderware\DASSIDirect\Log). The log must show "Connection Established" once at startup and a steady stream of read acknowledgements — no retry storms.

Troubleshooting Matrix

Performance, Limits, and Design Notes

• Poll rate. DASSIDirect default is 1000 ms. The LOGO! 0BA8 S7 server sustains 250–500 ms on small tag counts; below 200 ms the response time plateaus because the LOGO! scan time becomes the bottleneck.
• Tag-count ceiling. Keep the active item set under roughly 200 discrete plus 50 analog items to stay within the LOGO! 0BA8 S7 server capacity. Excessive polling generates S7 timeout retries and degrades the LOGO! scan.
• Redundancy. DASSIDirect supports redundant device objects, but the LOGO! 0BA8 S7 server is a single instance. Use redundant SCADA PCs with each running its own S7CP_200 connection; only one PC actively writes at a time, coordinated by the InTouch application.
• Security. The S7-200 protocol in LOGO! 0BA8 has no built-in authentication. Place the SCADA LAN behind a managed switch with an ACL, or terminate the path with a VPN/DMZ if the network extends beyond the plant floor.
• Alternatives. If a non-S7-200 client is preferred, LOGO! 0BA8 also exposes Modbus TCP on TCP/502 (server role) and S7 symbolic access with LOGO! 8.3+. The Modbus TCP path is more familiar to InTouch teams that already use the Wonderware MBTCP driver, but it does not expose network I/O bits in the same compact address scheme — the mapping is to Modbus holding/input registers.
• Multiple partners. The LOGO! 0BA8 S7 server supports a small number of simultaneous partner connections (typically 4). Add a second S7CP_200 object on a different SCADA node with a different local TSAP (e.g. 01.02) if a parallel historian is required.

FAQ