Editing LOGO! 8 Weekly Timer Setpoints from the TDE Display

Overview

The Siemens LOGO! 8 logic relay with a connected LOGO! TDE (Text Display) is one of the lowest-cost PLC/HMI combinations in industrial automation. It is widely deployed in irrigation panels, pump alternation, signage lighting, and HVAC scheduling. The Weekly Timer (B013) function block can store up to three independent on/off cams per instance, and the LOGO! 8 base module (depending on firmware revision) can host 250 of them. The first deployment challenge is that timer values are read-only on the display by default. To make them operator-editable, the message text must be configured with the parameter exposed as Setpoint (read/write), and the operator must execute the ESC-key entry sequence on the TDE.

This reference documents the full chain for an 8-pump scheduling application: enabling parameter exposure, configuring the message text, executing the TDE edit procedure, and verifying the values. The F-key alternative is also covered for sites where operators cannot be trusted to navigate the field-edit menus.

Target hardware: LOGO! 8 base module family 6ED1052-1x008-0BA0 and later, LOGO! TDE 6ED1055-4MH08-0BA0, LOGO!Soft Comfort V8.2 (Build 18 or later) or V8.3 / V8.4. Official reference: Siemens Industry Online Support — Weekly Timer (LOGO!) ID 109741041.

Prerequisites

Hardware

• LOGO! 8 Base Module (BM): 12/24RCE, 24CE, 230RCE, or 230RCEo. The 12/24RCE (6ED1052-1MD08-0BA0) is the most common for pump control — it provides relay outputs and accepts the 24 VDC sensor inputs that float switches normally require.
• LOGO! TDE 6ED1055-4MH08-0BA0. The TDE has its own 10/100 Mbit Ethernet port and connects to the second Ethernet socket of the BM. The TDE does not occupy a slot in the LOGO! program; it is a passive terminal that listens to message text broadcasts from the BM.
• Patch cable, Cat 5e or higher, RJ45, max 100 m between the BM and the TDE.
• 24 VDC power supply (for 12/24RCE/24CE) sized for the BM + TDE + I/O load. TDE consumption is approx. 60 mA at 24 VDC plus 25 mA backlight peak.
• microSD card (max 32 GB, FAT32) for program transfer if Ethernet is unavailable. Use a Siemens-branded card (6ED1057-1AA00-0BA0) where possible.

Software

• LOGO!Soft Comfort V8.2 or higher. Versions older than V8.2 do not support per-parameter Setpoint mode in the message text editor and cannot be used for this procedure.
• LSC project file (.lsc) with the Weekly Timer blocks already placed and their cam timing fields populated with the default schedule.

Knowledge prerequisites

• Familiarity with the LOGO!Soft Comfort circuit editor (FBD or LAD view).
• Understanding of the LOGO! 8 scan cycle: BM executes the program top-to-bottom, message text updates once per cycle, and the TDE polls the BM over Ethernet.

Weekly Timer (B013) — Technical Reference

The Weekly Timer is the LOGO! equivalent of a 7-day electromechanical programming clock. Each block instance contains three cams; each cam defines a daily on-time, off-time, and day mask. The block output Q is the logical OR of the three cams.

The Holiday parameter is supported on firmware V8.2 (FS:04) and later. On older firmware, the field is hidden in the LSC editor and the cam fires on every day in the mask, regardless of holiday status.

Message Text (B001) — Parameter Exposure

The Message Text block is the only standard way to display I/O, function block parameters, and free-form strings on the TDE. It is the gateway to the parameter-editing feature.

Block summary

• Up to 50 message texts per LOGO! 8 program (firmware-dependent; some FW revisions count "lines" instead of "blocks" — confirm with the LSC project validator).
• Each text is up to 4 lines long, 24 characters per line on the TDE.
• Inputs to the block are the parameters you drag onto its body in the LOGO!Soft Comfort editor. They can be actual values, setpoint values, or both.
• Each text has an enable input (En) and an acknowledgment input (Ack) — the Ack input is optional and used to dismiss an alarm-style message with the TDE OK key.

Drag-and-drop the Weekly Timer

1. Open the LSC project. Place a Message Text block (toolbox under Special Functions → Message).
2. Resize the block in the FBD view to expose the I/O field.
3. From the toolbox, drag a copy of the Weekly Timer block onto the message text body. LSC will automatically wire a parameter reference.
4. Right-click the parameter inside the message text body and select Properties. The properties dialog has two radio options:
   • Actual Value (read) — displayed but not editable.
   • Setpoint (read/write) — operator can change the value on the TDE.
5. Select Setpoint (read/write) for every Weekly Timer time parameter you want the operator to change. The on-time and off-time for each of the three cams is selectable independently; you can mix read-only display of Cam 1 and editable Cam 2.
6. Repeat for all eight pump-schedule message texts.

Text string and bargraph options

The message text supports embedded strings, embedded I/O names, and a bargraph variant. A typical pump-status message might look like:

Pump 1  Cam1: 06:00-09:00
Cam2: 17:00-20:00
Status: ON
Output: Q1

The Status line is wired to the Q output of the Weekly Timer (Actual Value). The two Cam lines are wired to the cam on/off times (Setpoint).

TDE Editing Procedure

Once the program with editable message text is transferred to the BM and the TDE is connected and showing the message, the operator performs the following sequence to edit a parameter in place.

1. Navigate to the message text on the TDE using the up / down cursor keys until the relevant pump screen is in view.
2. Press and hold ESC for at least 2 seconds. Release when a black horizontal bar appears superimposed on the first editable field.
3. Use up / down to move the black bar to the parameter you want to edit (for example, Cam 1 On time).
4. Press OK to enter the field. The cursor changes to a blinking underscore or block within the field.
5. Use left / right to position the cursor over the digit to change.
6. Use up / down to increment / decrement the digit. Holding the key auto-repeats at approximately 4 Hz.
7. Press OK to commit the change. The cursor returns to the black bar; the underlying value is updated immediately and sent back to the BM.
8. Move to the next field and repeat, or press ESC to exit edit mode.

Edit-mode state machine

Field conventions

TDE vs Onboard BM Display

The LOGO! 8 BM has a built-in 6-line display, but it is not designed for permanent installation in an enclosure door. The TDE provides the same operator experience plus a backlit LCD, four programmable F-keys, and a remote-mountable housing (panel cut-out 96 × 96 mm).

F-Key Increment / Decrement Alternative

For sites where the operator cannot be trusted to use the ESC-key entry, the F1–F4 keys on the TDE can be programmed as digital inputs. The four keys appear in the LOGO! program as inputs I1, I2, I3, I4 (cursor keys) and I5, I6, I7, I8 (F1–F4) on a per-display basis. Combined with an Up/Down Counter (B002), the operator can hold an F-key to nudge a setpoint value in real time without entering edit mode.

Program pattern

1. Wire an Up/Down Counter (B002) to one of the F-key inputs (I5–I8) configured as Count Up, and a different F-key as Count Down. Set the counter to retain across power cycles (Remanence = On).
2. Wire the counter's CV (current value) into the Weekly Timer cam On-time parameter. Convert the integer to HH:MM using an arithmetic instruction block — the LSC library includes a Time arithmetic operator.
3. Map the counter to a message text on the TDE with Setpoint disabled, so the operator sees the running value but cannot type — only the F-keys can change it.
4. Optionally, add a third F-key as a "Reset to default" that writes a fixed value to the counter via an analog flag.

This is the most rejection-proof configuration because the operator cannot enter an invalid time, cannot accidentally trigger ESC mode, and the panel remains locked-down.

8-Pump Application — Sample Configuration

The reference use case is an 8-page TDE menu where each page shows the schedule of one pump and exposes the on/off setpoints for editing. The data model is:

Commissioning steps

1. Build the program in LSC with eight Weekly Timer blocks (B013 #1 through B013 #8), each with two cams to allow a morning and an evening run window.
2. Add eight Message Text blocks (B001 #1 through B001 #8). In each, drag the corresponding B013 block onto the message text body and configure Cam 1 On, Cam 1 Off, Cam 2 On, Cam 2 Off as Setpoint (read/write).
3. Add a ninth Message Text block for the system status overview (current pump states, real-time clock, next scheduled run).
4. Connect the eight message text enable inputs to a navigation indexer driven by the F-keys (F1 = previous, F2 = next). The indexer can be a 4-bit Up/Down Counter whose CV is decoded into eight discrete flags.
5. Save and transfer the program to the BM via Ethernet or micro-SD card.
6. Connect the TDE to the second Ethernet port. Power cycle the BM after connection to allow the TDE to enumerate on the network.
7. Verify each message text page scrolls on the TDE and the time fields are visible.
8. Run the operator edit procedure on Pump 1 to change Cam 1 On from 06:00 to 06:30. Confirm the value persists across a power cycle.

Network Topology and Commissioning

The TDE is not a peer on the LOGO! network — it is a slave display on the second Ethernet port of the BM. The first Ethernet port of the BM can simultaneously connect to a programming PC, a LOGO! CMR (cloud module), or a higher-level SCADA via Modbus TCP. The TDE does not consume any IP address slot on the wider network; the only routable address is the BM's first port.

For a multi-panel installation, multiple BMs can be cascaded via the Ethernet interface and addressed from a single SCADA, but each BM must be paired with its own TDE — the TDE cannot poll a remote BM.

Verification and Acceptance Test

A formal acceptance test is recommended before site handover. Each acceptance step has a pass criterion that can be ticked off.

Troubleshooting Matrix

Field-Proven Tips and Caveats

• Never run the message text enable inputs through a Weekly Timer that itself uses an editable setpoint — if the operator disables the schedule, the menu vanishes with it.
• Keep the number of message text pages small. The TDE re-draws the screen on every page change, and a 50-page carousel can become sluggish with a slow-scan I/O network.
• When using the F-key alternative, the Up/Down Counter (B002) must be initialized with a sane value before first run. Use an analog flag or a startup pulse to write a default value on the first scan.
• The LOGO! 8 BM does not natively accept NTP. If the application requires IEC 61131-3 time-of-day synchronization, use a Siemens S7-1200 / S7-1500 with NTP client and a Modbus/TCP write to push the LOGO!'s RTC, or use a hardware RTC module.
• For multi-language sites, parameter labels in the message text respect the project language; load the appropriate LSC locale on the TDE via the Setup menu to avoid mixed-language screens.
• The BM has a finite number of resources. The exact block count is firmware-dependent. Refer to the manual for the FS revision in use: FS:04 supports up to 400 function blocks, FS:05 up to 400. The Weekly Timer has a relatively high resource cost; budget for it.
• Always test the TDE edit procedure at full system voltage, not at the bench supply. Some TDE units exhibit sluggish cursor response when supplied from a current-limited lab PSU.
• If the program includes a UDF (User-Defined Function) library block that wraps a Weekly Timer, parameter changes from the TDE may not propagate to the UDF. Edit the cam time at the UDF's exposed parameters, not the embedded B013.

FAQ