LOGO! 8.3 to 0BA5 Migration: Converting LSC Projects to LOGO! 5

1. Problem Overview

Siemens LOGO! Soft Comfort (LSC) projects created for the LOGO! 8.3 (0BA8.3) platform cannot be uploaded directly to a LOGO! 5 (0BA5) base module. When the PC transfers the program, LSC raises a hardware-type-incompatibility error and the download aborts. The error is not recoverable inside an existing .lsc file because the internal block list, block-name table, and text-message layout differ structurally between the 0BA8 and 0BA5 firmware generations.

This reference documents the manual migration path used when you must reuse the original logic on a 0BA5 hardware target: it identifies why the automatic hardware-type conversion in LSC fails, lists the specification deltas the engineer must absorb, and provides a step-by-step procedure for producing a clean 0BA5 program with verified upload.

2. LOGO! Generation Reference

Each LOGO! generation corresponds to a distinct 0BAx order code suffix and a minimum LSC editor version. Cross-generation LSC files are not interchangeable without a clean rebuild.

Reference: Siemens LOGO! product family overview at siemens.com/logo and the LOGO! manual set in the Siemens Industry Online Support portal at support.industry.siemens.com.

3. 0BA5 vs 0BA8.3 Hardware Specification Comparison

The functional and physical differences between the two targets are the source of every migration friction. Confirm the 0BA5 module order code on the nameplate before starting.

Reference: LOGO! 5 (0BA5) system manual and LOGO! 8 (0BA8) system manual, both available in the Siemens Industry Online Support portal under entry IDs 6ED1052-1xxxx for 0BA5 and 6ED1052-2xxxx for 0BA8.

4. Why Direct LSC File Editing Fails

LSC stores the program as an XML-like structure with three components that the editor maintains in lockstep:

1. Block-number table – Sequential block numbers B001, B002, B003…
2. Block-name table – User-assigned display names (e.g. Motor_Run)
3. Block-parameter record – Block type, pin connections, and constant values

When the file is downgraded by switching the Hardware Type dropdown in LSC from 0BA8.3 to 0BA5, the editor attempts to translate every block into its 0BA5 equivalent. If any block has no 0BA5 counterpart (e.g. newer special function blocks introduced in 0BA7/0BA8), the translation either silently drops the block, drops the parameter, or leaves the block-number table misaligned with the block-name table.

Three failure signatures appear consistently:

• Renumbered blocks with stale names: B005 carries the label of an originally-different block (e.g. B46). This indicates cross-file copy/paste into a partially-converted project.
• "Missing AI1" warning on conversion – the source used analog input AI1 in 0BA8 (which exists on 0BA8 I7/I8), but 0BA5 base modules do not expose AI1 without an AM2 module. The reference to AI1 is left dangling.
• Text-message overflow – text blocks longer than 4 lines × 12 characters are silently truncated on the 0BA5 display.

5. Prerequisites

6. Migration Procedure – Step-by-Step

1. Open the original 0BA8.3 file in LSC V8.x in read-only mode. Use File → Open and immediately export a PDF or screenshot of every diagram sheet for reference. Do not save changes.
2. Inventory the program. From the LSC Tools → Block List view, record: total block count, list of special function block (SFB) types, every text-message block, and every analog input reference.
3. Close the file. Do not attempt File → Save As with the 0BA5 hardware type selected.
4. Launch LSC V5.x (or use LSC V8.x with File → New followed by selecting 0BA5 hardware type before any programming).
5. Create a new project. File → New. In the hardware-type dialog, choose 0BA5 first. Do not place any blocks before this selection.
6. Configure the diagram area. Edit → Grid – confirm grid pitch. Set the diagram sheet count to match the original (or expand to multiple sheets with the matrix icon in the toolbar).
7. Re-enter the logic. Rebuild each function block manually using the printed reference. Use the Insert → Block menu. For every block you re-create, assign a new sequential block number (B001, B002…) and a clean block name – never copy/paste from the original 0BA8 file.
8. Re-wire the connections. Drag from each block's output pin to the next block's input pin. Confirm every input resolves (no red triangle).
9. Convert text messages (Section 7). Remove every text-message block from the 0BA8 source reference and re-create them under the 0BA5 formatting rules.
10. Convert analog references (Section 8). If the original used AI1/AI2 on 0BA8 base inputs I7/I8, remap to an AM2 expansion module's AI1/AI2.
11. Save the project. File → Save As with a new filename, e.g. project_0BA5_v1.lsc. LSC will warn if any block exceeds 0BA5 capacity – address every warning before saving.
12. Simulate. Tools → Simulation. Step through inputs and confirm outputs behave as in the original 0BA8 simulation.

7. Text Message Block Conversion (Critical)

The 0BA5 display is materially smaller than the 0BA8.3 display, and the on-board LOGO! TD (Text Display) is not supported on 0BA5. Every text block must be reformatted.

7.1 Conversion Procedure

1. Open each 0BA8.3 text block and identify every variable field (%AI1, %MW0, etc.).
2. Split lines exceeding 12 characters; if the meaning is lost, abbreviate or move text to a second message block.
3. Combine any line that exists below line 4 with line 4 (or move to another message block).
4. Verify bar-graph elements are removed – 0BA5 cannot render them.
5. Confirm the total text-block count does not exceed 10. If it does, delete lower-priority messages.

8. Function Block Compatibility Matrix

The following special function blocks (SFBs) and resources require manual translation when moving from 0BA8.3 to 0BA5.

If the source program uses any block flagged "No" above, the LSC Hardware Type change dialog will refuse the conversion or silently drop the block. Manual rebuild is mandatory.

9. Upload Procedure to LOGO! 0BA5

After the rebuild and simulation pass, transfer the program with the correct cable.

1. Power up the 0BA5 module. Connect 115–230 V AC (or 12/24 V DC depending on variant). Verify the display shows the date/time and "No Program" or the previous program name.
2. Connect the PC cable. Plug the LOGO! PC Cable (RS-232) or LOGO! USB Cable into the 0BA5's PC interface socket on the front face (under the display cover). Connect the other end to the PC.
3. Set PC COM port. In LSC V5.x: Tools → Options → Interface. Select the COM port (COM1 for native RS-232, virtual COM for USB).
4. Open the rebuilt .lsc file in LSC V5.x. Confirm the bottom status bar shows 0BA5 as the target hardware type.
5. Transfer. Tools → Transfer → PC → LOGO! (or click the down-arrow transfer button). LSC will compile and push the program.
6. Verify on the module. The 0BA5 display should show "PC <-> LOGO!" briefly, then return to RUN mode. Confirm with LOGO! → Start if the program was previously stopped.
7. Test under load. With the panel cover closed (RUN mode active), exercise every input. Watch the outputs and the on-board display.

10. Troubleshooting Matrix

11. Field Commissioning Notes

• Power budget check. 0BA5 base modules with relay outputs consume more inrush than 0BA8 transistor variants. Verify the upstream PSU can deliver the inrush without sagging below the LOGO! brown-out threshold.
• Retentive memory. 0BA5 supports retentive bits, counters, and timers, but the retentive area is smaller than 0BA8. Confirm every variable flagged as retentive in the 0BA8 source fits within the 0BA5 retentive memory map.
• Real-time clock. Only 0BA5.RTC variants include an RTC. If the original 0BA8 program used weekday or time-of-day logic, confirm the target module is the RTC variant (order code suffix ...-0BA1 for AC PSU with RTC, or ...-0BA2 for DC PSU with RTC).
• Expansion bus. 0BA5 supports DM8 / DM16 / AM2 / AM2 PT100 expansion modules on the right-side bus. Up to 4 expansion modules total (older firmware) or more on newer firmware revisions. Check the maximum count in the LOGO! 5 manual for the specific firmware revision on the module.
• Display contrast. 0BA5 has a fixed-contrast built-in display. The 0BA8 TDE (external text display) cannot be attached to 0BA5.
• Documentation: After upload, print the LSC diagram (FBD) and label the panel with the program filename, version, and date. Place the backup of the original 0BA8 source in the panel cabinet for traceability.
• Verification checklist:
  1. Every input forced via LSC simulation produces the expected output within one scan cycle.
  2. Every text message renders within 4 lines × 12 chars without truncation.
  3. Retentive values survive a power-cycle test (≥ 3 cycles).
  4. Softkey navigation cycles through menus correctly on the built-in display.
  5. If an RTC variant is used, confirm date/time persists after power-down.

12. Summary

The migration path from LOGO! 8.3 (0BA8.3) to LOGO! 5 (0BA5) is not a software conversion – it is a manual rebuild. LSC cannot safely downgrade an .lsc file across these two generations because the block libraries, text-message geometry, I/O map, and communication interfaces are fundamentally different. The engineer must start a fresh project, set the hardware type to 0BA5 before any logic is added, rebuild each block with sequential numbering, reformat every text message to 4 × 12 characters and ≤ 10 total messages, remove or substitute any 0BA7/0BA8-only blocks (astronomical clock, PWM, PI, UDF, network I/O), and then transfer the program via the LOGO! PC Cable or LOGO! USB Cable. Following the procedure in Sections 6 and 7 produces a stable 0BA5 program that runs identically to the original 0BA8 deployment within the limits of the older hardware.