1. Overview: Why Program a 0BA6 from the Keypad
The Siemens LOGO! 0BA6 (LOGO! Generation 6, launched in late 2008) is the first LOGO! generation where every standard and special function block in the firmware library can be inserted, parameterized, and wired directly from the device keypad. The 0BA6 Standard variants ship with a backlit 4-line × 12-character LCD and a six-button keypad. The 0BA6 Pure variants (6ED1052-2xx06-0BA6) ship without a display and are unsuitable for keypad-only programming because they expose only status LEDs; their typical use is cabinet mounting where the program is downloaded from LOGO!Soft Comfort.
Although the recommended engineering environment is LOGO!Soft Comfort V7.x or V8.x, several practical reasons justify programming a 0BA6 directly from the keys:
- No PC, LOGO! PC-cable (6ED1057-1AA01-0BA0), or Siemens SD card is available on site.
- A technician must insert a missing block or correct a timer parameter without removing the field wiring or interrupting the running process.
- Training in the connector model and menu tree without a software license cost.
- Recovery of a corrupted program where Soft Comfort cannot establish a serial link to the unit.
2. 0BA6 Hardware Variants and Identification
Identify the variant before designing, because I/O count, analog capability, and supply voltage differ between order numbers. The 0BA6 base modules are listed in the table below.
| Order Number (MLFB) | Display | Power Supply | DI | DO | AI |
|---|---|---|---|---|---|
| 6ED1052-1CC01-0BA6 | Yes | 12/24 V DC | 8 | 4 relay 10 A | 4 (0-10 V on I1, I2, I7, I8) |
| 6ED1052-1MD00-0BA6 | Yes | 24 V AC/DC | 8 | 4 relay 10 A | — |
| 6ED1052-1FB00-0BA6 | Yes | 115/230 V AC | 8 | 4 relay 10 A | — |
| 6ED1052-2CC01-0BA6 | No (Pure) | 12/24 V DC | 8 | 4 relay 10 A | 4 |
| 6ED1052-2MD00-0BA6 | No (Pure) | 24 V AC/DC | 8 | 4 relay 10 A | — |
The first digit of the suffix after the supply code identifies the housing form: 1 = with display, 2 = Pure (no display). The two middle blocks (CC, MD, FB) identify the supply voltage family. The four AI inputs on the 12/24 V DC variants are shared with I1, I2, I7, I8 and become AI1-AI4 when an analog sensor drives the input; the input then no longer appears as a digital in the program.
Expansion modules (max 24 DI / 16 DO / 8 AI total after expansion) attach on the right side. Use only modules of the same generation or newer, identified by a 0BA6 or higher suffix in their MLFB, because older 0BA0-0BA5 modules do not support the full SFB library of 0BA6 and may report an incompatibility on power-up.
3. Keypad Layout and Cursor Conventions
The 0BA6 keypad has six keys: ▲ (up), ▼ (down), ◄ (left), ► (right), OK, and ESC. Their function is consistent across all menus, and learning the convention is faster than memorizing per-screen key sequences.
| Key | In Menu | In Block List | In Parameter Editor |
|---|---|---|---|
| ▲ / ▼ | Move selection up/down in the active menu. | Scroll the block catalog (Co, GF, SF, Rs, Bn). | Increment/decrement the value at the cursor. |
| ◄ / ► | Switch between editable fields, tabs, or submenu items. | Switch between connector groups (inputs / output / parameter). | Move the cursor between digits or fields. |
| OK | Open the highlighted submenu or confirm an action. | Insert the highlighted block, then open the connector assignment. | Save the parameter value and return to the connector screen. |
| ESC | Move up one level in the menu tree without saving. | Cancel block insertion; return to the previous block. | Discard the current edit; do not commit the value. |
During parameter editing, holding ▲ or ▼ produces a fast-rewind through the value range. For a 30 s timer, the value can be entered as 30.0 s, 0:30 m:s, or 0:00:30 h:m:s, depending on which unit the cursor sits on. Switching the cursor to a different time base with ◄ or ► converts the existing value to the new base automatically.
4. Display Map and Menu Tree
The 0BA6 main menu is reached by pressing ESC from the run-time display until the top-level Program / Card / Setup line appears. The tree is fixed across all 0BA6 firmware revisions (FW 1.x and 2.x for 0BA6).
The Setup branch contains the items the 0BA6 user can configure without entering the program editor: I/O display names (max 8 chars), start-up message text, M8 / M25-M27 retention, power-on delay (0.0 s - 60.0 s), and display backlight (auto / on / off). The Card branch manages the optional Siemens SD card (6ED1057-1AA00-0BA0, up to 8 MB) and program copy operations; the 0BA6 cannot use the card for live parameter override, only program image transfer.
5. Program Editor Model: Numbered Blocks and the Connector Concept
The 0BA6 editor stores programs as a list of numbered blocks. Each block has a unique number (B001, B002, B003...) and either executes logic (GF for general function, SF for special function, Co for constant) or stores data (Rs for latching, Bn for binary marker). The wiring between blocks is symbolic: a block's output is referenced as a connector name on a downstream block's input.
When you press OK on an empty line, the catalog appears in the order:
- Co (Boolean constant: hi = 1, lo = 0)
- GF (general function: AND, OR, NOT, NAND, NOR, XOR, XNOR)
- SF (special function: timers, counters, latching, PI, etc.)
- Rs (latching relay, set / reset dominant)
- Bn (binary marker / digital flag)
A typical signal chain is: input terminal (I1-I8) -> block B001 -> block B002 -> ... -> output terminal (Q1-Q4). The editor wraps to a new line automatically when the right side of the display is filled, and the current block number is shown on the left of each line. Connections are made by assigning a connector name to each block input; the editor does not draw wires between blocks, only the symbolic wiring is stored.
6. I/O Map, Markers, Shift Register, and Open Connectors
The 0BA6 connector namespace is fixed by firmware and cannot be extended. Use the table below as the reference for all assignments.
| Namespace | Range | Use | Retention |
|---|---|---|---|
| I (digital inputs) | I1 - I8 (base) plus expansion up to I24 | Wired to pushbuttons, sensors, contactors | Live; not retentive |
| AI (analog inputs) | AI1 - AI4 (DC variants only, on I1 / I2 / I7 / I8) | 0-10 V sensors; 12-bit resolution | Live |
| Q (digital outputs) | Q1 - Q4 (base) plus expansion up to Q16 | Drives relay or transistor outputs | Live |
| AQ (analog outputs) | AQ1 - AQ2 (on 0BA6 expansion AM2 AQ) | 0-10 V / 4-20 mA via expansion | Live |
| M (digital markers) | M1 - M27 | Internal flags for state, edge, and interlock | M8, M25, M26, M27 retentive (Setup) |
| AM (analog markers) | AM1 - AM6 | Internal 16-bit analog flags for math blocks | Non-retentive by default |
| S (shift register bits) | S1.1 - S4.8 (4 registers × 8 bits) | Sequence tracking, step chains | Retentive |
| X (open connectors) | X1 - X? (drawn from GF catalog) | Signal fan-out without duplicating a wire | Live |
| Constant hi/lo | 1 / 0 (Co block) | Hard-wired 24 V or 0 V signal for latches and defaults | Live |
7. Function Block Reference for Manual Programming
The block catalog visible from the keypad on 0BA6 is shown in the table below. Items are grouped by GF (general function) and SF (special function). Select the block, press OK, then assign the connector at the prompt.
| Group | Block | Inputs (typical) | Parameters | Output |
|---|---|---|---|---|
| GF | AND | Up to 4 | — | 1 |
| GF | OR | Up to 4 | — | 1 |
| GF | NOT | 1 | — | 1 (inverted) |
| GF | NAND / NOR / XOR / XNOR | 2 | — | 1 |
| SF | On-delay | Trg, R | Ta (0.01 s - 99:59 h) | Q |
| SF | Off-delay | Trg, R | Ta | Q |
| SF | On-/Off-delay | Trg, R | Th, Tl | Q |
| SF | Retentive on-delay | Trg, R | Ta | Q |
| SF | Pulse generator / flasher | Trg, R | Th, Tl (1 ms - 99:59 h) | Q |
| SF | Pulse relay / edge-triggered | Trg, R | — | Q |
| SF | Latching relay | S, R | Run / Stop mode | Q |
| SF | Up / down counter | In, Dir, R | Limit On, Limit Off | Q |
| SF | Hours counter | In, R, En | MN (maintenance interval) | Q |
| SF | Threshold trigger (analog) | In | On, Off, gain, offset | Q |
| SF | Analog comparator | Ax, Ay | On, Off, gain, offset | Q |
| SF | Analog threshold trigger | In | On, Off, gain, offset | Q |
| SF | Analog ramp | In, R | Gain, Offset, L1, L2, sp | Q |
| SF | PI controller | PV, SP, Dir, R | KC, TI, Dir | Q |
| SF | Weekly timer | — | 3 on/off cam pairs per channel | Q |
| SF | Yearly timer | — | On date, Off date | Q |
| SF | Message text | En, P, Ack | Text, T_on, T_off | Q |
8. Step-by-Step: Building a Stairwell Light with Auto-Off
The classic stairwell lighting circuit (pushbutton start, automatic off-delay, indicator light) is small enough to fit in one block and is the recommended first program. It demonstrates input wiring, SF parameter editing, and output assignment.
Specification.
- Input I1 = NO pushbutton at the door.
- Output Q1 = stairwell light relay.
- On-delay 0 s, off-delay 60 s. The light must go off 60 seconds after the last button press.
Procedure.
- Power on. The display shows the run-time screen; press ESC repeatedly until Program is highlighted.
- Press OK, then select Edit Program and press OK. If a password prompt appears, the program is protected; the password is four characters and entered with ▲ / ▼ for the digit and ► / OK to commit.
- Press OK on the empty line. The catalog opens at Co. Press ▲ three times to move to SF (special function) and press OK. The first item is the on-delay; press ► to move to Off-delay and press OK.
- The block is inserted as B001. The display shows B001 on the left and the input field Trg on the right. Press OK to assign the trigger.
- The connector list opens. Press ▲ / ▼ until I1 is highlighted, then press OK twice (once to confirm, once to close the input prompt).
- Press OK on the block to enter parameter mode. ► jumps to the time field; ▲ sets the first digit to 0, ► moves to the seconds, ▲ sets 60. OK commits and returns to the connector screen.
- Press ► to move to the output field Q of B001. Press OK, then ▲ / ▼ to Q1 and press OK twice.
- Press ESC twice to save. The display shows Save program?; highlight Yes and press OK. The program is now in RUN.
Verification without PC.
- Press the pushbutton at I1. The status of Q1 in the run-time display toggles to 1 within 50 ms (firmware scan time, 0.6 ms - 8 ms typical for 200 blocks on 0BA6).
- Release the button. Q1 must remain 1 for 60 s ± 1 s, then return to 0.
- Repeat the test three times; if the timing drifts, check the parameter entry for a stray decimal point.
9. Using LOGO!Soft Comfort Demo as an Offline Drafting Tool
The free LOGO!Soft Comfort demo (V7.x for 0BA6 projects, V8.x for cross-development) is bundled on the Siemens LOGO! product DVD and is available from the official Siemens Industry Online Support. It can read, write, simulate, and document 0BA6 programs, but it cannot transfer a program to a real LOGO! over a serial or USB PC-cable. Use it as follows:
- Install the demo on a Windows PC. The installation does not require a license key.
- Select File -> New -> LOGO! 0BA6 Standard as the target. The I/O count in the FBD editor is matched to the chosen base module.
- Draft the program in FBD or Ladder view. Use the connector labels exactly as the 0BA6 firmware expects (I1, Q1, M8, B001, etc.).
- Press F5 to start simulation. The demo simulates I/O, timers, counters, and message texts. The simulation runs at the same code path as the real firmware, so a program that simulates correctly will also run correctly on a 0BA6 of the same MLFB.
- Print the program (Ctrl+P, FBD with connector names option). Carry the printout to the cabinet; the printout is the draft to be entered block-by-block on the device keypad.
This workflow is the best of both worlds: the demo handles simulation, documentation, and revision tracking, while the on-device editor is used only for the final transfer. It is also how to validate a manual entry against a known-good design: if the demo's simulation matches the on-device behavior, the manual entry is correct.
10. Program Memory, Block Limits, and 0BA6 Firmware Notes
The 0BA6 has a 4000-byte program memory that holds up to 200 function blocks, including markers. Beyond that, the editor refuses to insert a new block. Firmware updates for 0BA6 are released on the Siemens Industry Online Support portal and are field-loaded via the SD card.
| Resource | Limit on 0BA6 | Hard error if exceeded |
|---|---|---|
| Function blocks (GF + SF + Co + Rs + Bn) | 200 | Memory full message, OK to retry after deleting a block |
| Program memory | 4000 bytes (3400 memory words) | Insert blocked; delete or compress |
| Cycle time | 0.6 ms - 8 ms typical, FW-dependent | Cycle time alarm in display; > 50 ms halts outputs |
| Analog blocks | 15 (recommended) - 30 (firmware max) | Higher values degrade cycle time |
| Message text blocks | 50 (firmware 2.x), 16 (firmware 1.x) | Insert blocked |
| Weekly timer cam pairs | 3 per weekly timer, 3 weekly timers in firmware 2.x | Insert blocked |
| Password length | 4 ASCII characters (numeric / A-Z) | — |
Cycle time alarm is the most common error in a hand-entered program: a chain of 200 SF blocks with multiple weekly timers can exceed 50 ms. The display shows the actual cycle time in the Info branch of the menu; if the value is above 50 ms, remove or simplify blocks before commissioning.
11. SITRAIN, Starter Kits, and Continuing Education
Siemens SITRAIN offers the LOGO! System Course covering the 0BA6 to 0BA8 generations. The course is delivered as a 1-day classroom session, a 2-day blended session with a virtual lab, or a 3-hour web-based training. Topics include the connector model, FBD editor use, SD card handling, and integration with LOGO! 8 cloud connections.
For self-study, the Siemens Industry Online Support article library hosts the LOGO! manual, the LOGO!Soft Comfort help file, and the application example set. The application example set covers 50+ programs grouped by application: lighting, gate control, pump alternation, conveyor sequencing, and HVAC. A web-based training and a PowerPoint deck with detailed system explanations are also available from the SITRAIN portal.
A starter kit (0BA6 generation) typically contains a LOGO! 12/24 RCE, a PC-cable, a manual, and a full LOGO!Soft Comfort license. The kit is the most cost-effective way to obtain a license that can transfer programs to hardware. Confirm the exact kit contents and order number with the local Siemens distributor, as the bundle changes between 0BA6, 0BA7, and 0BA8 generations.
12. Common Errors and Onboard Diagnostics
The 0BA6 onboard display reports a small set of error codes that the keypad programmer should memorize. The table below covers the codes that appear in 0BA6 firmware 1.x and 2.x.
| Display text | Cause | Action from keypad |
|---|---|---|
| Memory full | 200 blocks / 4000 bytes exceeded | Delete unused block, then reinsert |
| Block not connected | An input is unassigned | Move cursor to the input, press OK, assign a connector or X (open) |
| No program | Card transfer failed or memory erased | Recreate program from draft or card |
| Cycle time exceeded | Long scan detected (> 50 ms) | Reduce block count or simplify timers |
| Password? | Program is protected | Enter 4-character password; if forgotten, master reset clears password but also clears program |
| Set clock | Power-off > 24 h with no battery | Set RTC in Program -> Set Clock; 0BA6 has no battery option, RTC must be re-set after every power-off |
| Card error | SD card format or read error | Re-format card on PC, copy program again |
The master reset procedure is the same for all 0BA6 variants: power off, hold all four cursor keys, power on. The display shows Reset?. Highlight Yes and press OK. The program, password, and message texts are erased. Use this procedure only as a last resort; once the program is gone it must be re-entered block-by-block.
13. FAQ
Can a 0BA6 be programmed from the keypad without the LOGO! TD text display?
Yes. The 0BA6 Standard variants include an integrated 4-line LCD; the TD is optional and only used to free up I/O by relocating the HMI. The 0BA6 Pure variants cannot be programmed from any keypad because they have no display or keys.
How many function blocks fit in a 0BA6 program?
Up to 200 function blocks (GF, SF, Co, Rs, Bn combined) within 4000 bytes of program memory. The editor refuses to insert a new block with the message Memory full once either limit is reached.
Why does my analog input show n.a. in the AI menu?
The 0BA6 only supports analog inputs on the 12/24 V DC base variants. On 24 V AC/DC and 115/230 V AC units, the AI menu is intentionally hidden by firmware. Verify the MLFB suffix; only 6ED1052-1CC01-0BA6 and 6ED1052-2CC01-0BA6 expose AI1-AI4.
Can the LOGO!Soft Comfort demo transfer a program to my 0BA6?
No. The demo can read, edit, simulate, and document 0BA6 programs, but it cannot write to a real LOGO!. A full LOGO!Soft Comfort license is required for transfer via the PC-cable (6ED1057-1AA01-0BA0) or SD card (6ED1057-1AA00-0BA0).
What is the typical cycle time of a 0BA6 program?
0.6 ms to 8 ms for a fully populated 200-block program, depending on firmware revision. The display shows the live cycle time in the Info menu. If the cycle exceeds 50 ms, the firmware halts all outputs and reports Cycle time exceeded.