Resolving LOGO! 8 Ticker Direction Reversal on FS06 Firmware

The LOGO! 8 onboard Ticker function is a widely used display feature for message text on the LOGO! base module's integrated display and on the optional LOGO! TDE external text display. On certain LOGO! 8 hardware configurations, the Ticker exhibits a firmware defect where the message text scrolls to the left for three full cycles, then reverses direction and scrolls to the right. This article documents the affected part numbers, the firmware behavior, the Siemens technical support findings, the verified workarounds, and the field-procedure for hardware replacement and verification.

1. Problem Statement: Ticker Direction Reversal

The Ticker characteristic of the Message Text function block in LOGO!Soft Comfort is intended to scroll a configured text string horizontally across the active line of the display. The direction is not user-configurable; the firmware is expected to scroll the text consistently in one direction (left-to-right text reading order; visually scrolling to the left) for the duration of the active message.

On affected hardware, the following behavior is observed on the LOGO! integrated display (and on a connected LOGO! TDE if the message is routed to that target):

1. The text scrolls to the left for the first three full cycles.
2. On the fourth cycle, the text scrolls in the opposite direction (to the right).
3. The pattern repeats: three left, one right, three left, one right, indefinitely.

The Ticker function has no directional parameter exposed in the engineering software; the reversal cannot be suppressed by configuration. The issue is not present on LOGO! 6 hardware, on LOGO! 8 with FS04 firmware, or on LOGO! 8.2 (FS01) hardware, and is not reproducible in the LOGO!Soft Comfort simulation environment when the program is run on a known-good device.

2. Affected Hardware and Software

The defect has been confirmed on the following part numbers and firmware states:

Software versions tested against the affected hardware:

The software version is not the source of the defect. Identical programs written in V8.1.1 and V8.2.0, transferred to the affected FS06 hardware, both exhibit the direction-reversal pattern. The defect is firmware-resident on the base module and is independent of the engineering toolchain.

3. Root Cause Analysis

Siemens technical support reviewed a video of the issue, reproduced the behavior on a 0BA8 FS06 device using LOGO!Soft Comfort V8.2.0, and confirmed that the Ticker direction is not a user-configurable parameter. The defect is a firmware-level bug in the Ticker display routine of the FS06 base module firmware.

The Ticker algorithm on the affected firmware initializes a left-direction scroll, but the scroll-direction register or its reset condition is not handled correctly: after three complete cycles (where one cycle is defined as the time for the text to enter from the right edge of the display, traverse the line, and exit from the left edge), the firmware inverts the direction. The inversion repeats on every fourth cycle, producing the observed 3:1 left:right pattern. The inversion is hard-coded in the FS06 firmware and is not user-accessible.

3.1 State Diagram of the Defect

The following state diagram illustrates the observed Ticker behavior on the affected FS06 hardware. Each state represents one complete scroll cycle, defined as text entering from the right, traversing the display, and exiting on the opposite edge.

4. Reproduction Procedure

To reproduce the defect on a suspect FS06 device, use the following minimal test program and observation procedure. The procedure is suitable for first-pass screening of suspect hardware and for verifying a replacement unit after RMA.

4.1 Test Program Construction

1. Open LOGO!Soft Comfort V8.2.0 and create a new project (File > New).
2. From the function block library, insert a Message Text block (Special Functions > Message Text).
3. Configure the Message Text block as follows:
   • En (enable): Connect to a digital input, or tie to a constant high (logo! high).
   • P1, P2, P3, P4 (priority): Leave all at logic 0 (lowest priority).
   • Message text line 1: Enter a fixed ASCII string of at least 12 characters, for example: HELLO WORLD 1234
   • Ticker characteristic: Enable (check the Ticker box).
   • Display target: Onboard LOGO! display.
   • Character set: Western (default).
   • Acknowledgment: Disabled.
4. Save the program as ticker_test.lsc and download to the target LOGO! 8 device (PC -> LOGO! transfer).
5. Place the LOGO! in RUN mode.

4.2 Observation Procedure

1. Power the LOGO! from a clean supply (within the device's rated range) and observe the message text on the integrated display.
2. Count the number of complete left-direction scroll cycles. One cycle = text fully enters from the right edge, traverses the line, and exits on the left edge.
3. Observe the direction of the fourth cycle.
4. Continue observation for at least 10 cycles to confirm the 3:1 pattern is stable.

Expected result (defective FS06 firmware): Three left-direction cycles, one right-direction cycle, repeating.

Expected result (correct firmware): Continuous left-direction scrolling for all observed cycles.

5. Siemens Technical Support Findings

The defect was escalated through standard Siemens support channels. The following is a summary of the technical support findings as reported by Siemens Industry Automation and Drive Technologies support:

• The defect was reproduced by Siemens support on a 0BA8 FS06 device using LOGO!Soft Comfort V8.2.0.
• Siemens support confirmed that only LOGO!Soft Comfort V8.1.1 and V8.2.0 are fully compatible with the affected LOGO! 8 FS04 and FS06 hardware.
• Siemens support confirmed that the Ticker function has no direction parameter exposed in the LOGO! 8 firmware.
• Siemens support was unable to identify a configuration workaround and recommended device exchange.
• The case was escalated to Siemens Germany for firmware-level investigation; no firmware fix has been published for the LOGO! 8 (0BA8) base module as a result.

The official Siemens remediation is replacement of the affected base module with a unit of a confirmed-good firmware state (FS04 of the same part family, or a LOGO! 8.2 (FS01) unit of an equivalent I/O configuration). The replacement process is described in Section 7.

6. Workarounds and Mitigations

Because the firmware defect cannot be patched in the field, the available workarounds are limited to hardware substitution and program-level alternatives. Evaluate each option against the application requirements (supply voltage, I/O count, analog support, communication interfaces) before selecting a remediation path.

6.1 Option 1: Hardware Replacement (Recommended)

Replace the affected base module with a unit of a confirmed-good firmware state. The following alternatives have been verified in field use:

6.2 Option 2: Program-Level Alternatives

If hardware replacement is not feasible in the short term, the following program-level alternatives eliminate the Ticker defect entirely by avoiding the affected firmware routine.

1. Static message text. Disable the Ticker characteristic in the Message Text block. The message text displays as a static string. This is the simplest workaround and has no firmware-side direction handling.
2. Multiple message text blocks with alternating enable logic. Use two or more Message Text blocks with the Ticker characteristic disabled and rotate the active block using a clock-pulse generator (e.g., 1 Hz on/off pulse). This produces a flash/alternation effect without horizontal scrolling.
3. Bar graph only. Replace the Ticker message with a bar graph indicator driven by an analog or digital value. The bar graph display routine is not affected by the Ticker defect and provides a clear at-a-glance status.
4. External LOGO! TDE. Route the message text to a LOGO! TDE external text display. Verify that the TDE's own firmware is current; the TDE was not implicated in the original defect report and is generally a sound mitigation, but verify before relying on it for a customer-facing application.

6.3 Option 3: Reduce Cycle Count

If the Ticker characteristic cannot be avoided and hardware replacement is delayed, observe whether a 3-cycle limit can be enforced by using the message text acknowledgment (Ack) input to clear and re-trigger the message at the third cycle boundary. Each re-trigger resets the ticker counter on the affected firmware. This approach is application-dependent and has not been verified across all firmware variants; treat it as a contingency rather than a primary fix, and verify with a 30-minute observation under all operating modes.

6.4 Workaround Selection Matrix

7. Hardware Replacement Procedure

Use the following procedure when substituting the affected base module. The procedure assumes the replacement unit has the same form factor and I/O count; for different form factors, adapt the wiring and configuration steps accordingly.

1. Capture the program. In LOGO!Soft Comfort, perform an Upload from LOGO! or open the existing project file. Save a backup copy of the project (.lsc) with a versioned filename.
2. Document the wiring. Photograph or sketch the existing terminal wiring, including supply (L1/N for AC; 24V/0V for DC), inputs (I1..I8 or up to I1..I24 with expansion), and outputs (Q1..Q4 or up to Q1..Q20 with expansion). Note the I/O tag assignments used by the program.
3. Power down. Isolate the supply to the LOGO! base module using the upstream disconnect and verify zero energy at the supply terminals with a meter.
4. Remove the affected unit. Detach the terminal blocks and the base module from the DIN rail or panel mount. For LOGO! 8 installations with expansion modules, note the expansion bus order so the modules can be re-installed in the same sequence.
5. Install the replacement. Mount the new base module on the DIN rail, reattach the expansion modules in the original order (left-to-right bus order), and reseat the terminal blocks with the correct orientation.
6. Rewire to the documented assignment. Apply the original wiring, double-checking supply polarity on DC variants and phase/neutral on AC variants. Re-torque the terminal screws to the rated value.
7. Download the program. Connect the PC running LOGO!Soft Comfort, select the correct LOGO! type in the software (Tools > Select Hardware), and download the program. Use the PC -> LOGO! transfer dialog and acknowledge any firmware-compatibility warning if prompted.
8. Verify I/O operation. Place the LOGO! in RUN mode. Force each input from the source (sensor, switch, or simulation) and observe the corresponding output. Compare against the documented I/O assignment.
9. Verify the Ticker function. If the program uses the Ticker, run the reproduction procedure from Section 4 and confirm at least 10 cycles of consistent left-direction scrolling. If the direction reverses, the replacement unit is itself defective and should be quarantined for return.
10. Return the affected unit. Tag the affected unit with the support case number, the FS state, and the RMA reference. Pack in anti-static packaging and ship per the regional RMA procedure.

8. Compatible Firmware and Software Matrix

Use the following matrix to select the correct combination of LOGO! base module firmware and LOGO!Soft Comfort version. Compatibility is a function of the base module's FS (firmware state) designation; higher LOGO!Soft Comfort versions are generally backward-compatible with the FS levels they list in their compatibility dialog.

Legend:

• Compatible: Full feature support; program transfers and runs without warnings.
• Limited: Partial feature support; some function blocks or display features may not be available, or a compatibility warning is shown at transfer.
• Not compatible: The software cannot target the hardware; a different LOGO!Soft Comfort installation is required for the affected unit.

For the latest compatibility information, consult the official Siemens LOGO! software page and the version compatibility table in the LOGO!Soft Comfort installation package.

9. Ticker Function Programming Reference

The Ticker characteristic is a property of the Message Text function block in LOGO!Soft Comfort. The following parameter map summarizes the configurable inputs and properties relevant to the Ticker behavior.

Direction control: The Ticker property has no direction sub-parameter. The firmware determines scroll direction. On LOGO! 6 and on the unaffected LOGO! 8 firmware states, the direction is consistent (left). On the affected FS06 firmware, the direction inverts after three cycles.

Display line capacity: The onboard LOGO! display shows one line of up to 16 characters at a time when the Ticker is active. The LOGO! TDE external text display shows one line of up to 24 characters at a time. Strings longer than the display width trigger the Ticker behavior automatically when Ticker is enabled; strings shorter than the display width do not scroll.

Sample parameter block (LOGO!Soft Comfort V8.2.0):

Block: Message Text (B001)
  En:    I1
  P1:    0
  P2:    0
  P3:    0
  P4:    0
  Ack:   0
  Line1: "HELLO WORLD 1234"
  Line2: (empty)
  Line3: (empty)
  Line4: (empty)
  Line5: (empty)
  Line6: (empty)
  Ticker: ON
  Display: Onboard + TDE
  Character set: Western
  Bar graph: none

10. LOGO! 8 Product Family Specifications

For context and to support replacement decisions, the following table summarizes the LOGO! 8 base module specifications relevant to this defect. Specifications are drawn from the official Siemens product documentation; verify against the device label and the documentation shipped with the unit before commissioning.

For the full product overview, refer to the Siemens LOGO! Product Overview PDF.

The LOGO! 8 (0BA8) generation covers a wide range of supply and I/O variants. The 6ED1052-1xx00-0BA8 part numbering follows the Siemens convention where the 5th and 6th characters encode the supply and I/O type. Verify the part number and FS state on the device label before commissioning a replacement; the FS state is typically printed on a small label on the side or back of the base module.

10.1 Part Number Decode (6ED1052 family)

11. Field Commissioning Verification

After replacement, run the following verification sequence before handing the system back to operations.

1. Visual check. Confirm the device label, FS designation, and supply rating match the documentation. Photograph the label and attach to the commissioning record.
2. Power-on test. Apply supply within the rated range and verify the LOGO! boot sequence completes (the LOGO! display shows the configured message text or the default start screen within 5 seconds).
3. Program transfer check. Confirm the program is the intended version. Use LOGO!Soft Comfort's Compare function (Online > Compare) to verify the on-line program matches the off-line source.
4. I/O walk-down. Force each input from the source (sensor, switch, or simulation) and observe the corresponding output. Record the result for each input and output address used by the program.
5. Ticker verification. Run the reproduction procedure from Section 4 and confirm at least 10 cycles of consistent left-direction scrolling. If the direction reverses, the replacement unit is itself defective and should be quarantined for return.
6. Communication check. If the LOGO! is networked (Modbus TCP, Ethernet, or S7 communication), verify the network connection and the data exchange with the master or HMI. Check that the polling registers return expected values.
7. Documentation update. Record the new device's serial number, FS state, and replacement date in the asset register. Update the support case with the resolution and the RMA reference. File the commissioning record with the project documentation.

12. Escalation and Support Path

When the defect is observed, follow this escalation path to obtain a replacement or a confirmed firmware fix.

1. Document the defect. Capture a video of the message text display showing at least 5 cycles of the 3:1 pattern. Note the device part number, FS state, and LOGO!Soft Comfort version on the video.
2. Open a Siemens support request. Use the regional Siemens Industry Online Support portal. Attach the video and the project file (.lsc). Reference the part number (e.g., 6ED1052-1HB00-0BA8) and the FS state (e.g., FS06).
3. First-line response. Siemens first-line support may attempt a configuration workaround (e.g., downgrading to LOGO!Soft Comfort V8.1.1) or recommend a hardware exchange. Provide the project file and a clean reproduction procedure.
4. Escalation to Siemens Germany. If the defect is reproducible and not resolved by first-line support, request escalation to Siemens Germany Industry Automation and Drive Technologies support. Reference the support case number.
5. RMA and replacement. If a hardware exchange is approved, follow the regional RMA procedure. Retain the affected unit for analysis until Siemens confirms the defect and closes the support case.

For self-service updates, firmware notes, and software downloads, the official Siemens LOGO! software page is the authoritative source. For product family specifications, refer to the Siemens LOGO! Product Overview PDF.

12.1 Troubleshooting Matrix

13. Frequently Asked Questions