Problem Description
On a Siemens LOGO! TDE (Text Display Extension) attached to a LOGO! 8 (0BA8 / 0BA8 FS04) logic module, the operator presses ESC > Setup > Switch to Admin, enters (or skips) the password, and the unit immediately returns "Failed to submit" on the bottom line. The Program tab remains disabled and no parameter change is accepted.
This symptom blocks every administrative function that the TDE is supposed to expose: editing messages, changing the LOGO! access password, modifying date/time, configuring network parameters, and uploading/downloading the circuit program to/from the base module. The TDE behaves as if the keystroke was rejected, but the rejection is not a password issue — it is a link issue.
| Affected hardware | Article number | Firmware range |
|---|---|---|
| LOGO! TDE (2-line, 6 buttons) | 6ED1055-1MD00-0BA2 | FW ≤ 1.04.x (TDE) on LOGO! 0BA8 base |
| LOGO! 0BA8 Standard | 6ED1052-1MD08-0BA0 / ...1HB00 | FW 1.08.x … 8.x |
| LOGO! 0BA8 FS04 | 6ED1052-1MD08-0BA1 | FW 8.x … 8.4 |
| LOGO! 8.3 / 8.4 base | 6ED1052-2MD08-0BA0 / 2HB00 | FW 8.3 / 8.4 |
Root Cause: TDE Has No Live Ethernet Connection to the LOGO! Base
Every administrative write performed from the TDE — including a permission-level change — is transmitted over Ethernet/IP to the LOGO! 0BA8 base module. The TDE is a pure I/O terminal in this respect: it does not own a copy of the program and it does not authorize changes locally. When the keystroke "Switch to Admin" is processed, the TDE wraps the request in an S7-compatible frame and POSTs it to the base module. If no TCP session is open, or the configured peer IP is unreachable, the TDE's internal state machine cannot complete the write and returns FAILED TO SUBMIT on the second display line.
Three link-state conditions all surface as the same error string:
-
No Ethernet cable plugged in (TDE has no DHCP link, displays
NO LINKon the status line). - Cable plugged in, but the target IP is wrong, missing, or still on factory default (TDE has link, but the configured peer does not answer ARP).
- TDE set to point to itself or to a non-LOGO! device (SYN sent, RST received, write times out).
Network Architecture — What the TDE Actually Does
The LOGO! TDE sits downstream of the LOGO! 0BA8 base module on the same Ethernet segment. From the base's point of view the TDE is just another Modbus TCP / S7-communication client. The TDE itself contains:
- An Ethernet port (10/100 Mbit, RJ45, no PoE) with its own MAC.
- A static IPv4 address with subnet mask and gateway — configured locally on the TDE or by DHCP if the base is acting as DHCP server.
- A peer entry called the LOGO! selection — the IP of the LOGO! 0BA8 base it will talk to.
- A dedicated LOGO! access password slot, stored locally on the TDE, that is sent on every write to the base.
The TDE does not require the program tab to be open, nor does it require LOGO! Soft Comfort, to authorize settings. The access level stored in the TDE is purely a client-side convenience (operator vs. admin vs. password) that determines which TDE keys are accepted. The actual authorization is verified server-side by the LOGO! base. A write attempt with no live link always fails server-side verification and is reported as FAILED TO SUBMIT.
Solution: Re-establish the Ethernet Link and Re-Issue the Admin Switch
Step 1 — Verify the Physical Link
- Connect a known-good Cat5e or better patch cable from the TDE RJ45 to the LOGO! 0BA8 base RJ45 (or to the same switch if the install uses a switch).
- On the TDE's idle screen, confirm that the network symbol on the second line shows two arrows, not a crossed-through icon.
- On the LOGO! base, the
LINKLED next to the RJ45 must be solid green; theACTLED must flicker when the TDE is polled.
Step 2 — Assign the TDE an IP Address
From the TDE front panel:
- Press ESC to enter the main menu.
- Navigate to Setup → Network → IP Address.
- Enter an IPv4 address on the same subnet as the LOGO! base. Default LOGO! 0BA8 base IP is
192.168.0.10with mask255.255.255.0; assign the TDE e.g.192.168.0.20. - Confirm with OK. The TDE reboots the network stack (does not power-cycle).
Step 3 — Bind the TDE to the LOGO! Base (LOGO! Selection)
This is the step most often missed and the direct cause of the FAILED TO SUBMIT message:
- Press ESC → Setup → LOGO! Selection.
- Use the cursor keys to enter the IP of the LOGO! 0BA8 base (e.g.
192.168.0.10). Press OK. - The TDE pings the configured peer. If the base responds, the TDE displays the LOGO! firmware version, serial number and name. If the field stays blank, repeat Step 1 and check the switch/VLAN.
0.0.0.0, the TDE has no valid peer and every administrative write — including Switch to Admin — will fail with FAILED TO SUBMIT. This is the dominant root cause in the field.Step 4 — Switch to Admin and Enter the LOGO! Password
- Press ESC → Setup → Switch to Admin.
- The TDE now prompts
PASSWORD:. Enter the LOGO! base access password (factory default:LOGO). - Press OK. The TDE transmits a write to the base. A successful response changes the right-hand corner of the display to
ADMINand unlocks the Program tab.
Verification
After the four steps above, validate that admin rights are actually held by the TDE and not just displayed:
- Program tab on the TDE is no longer greyed out — press the up arrow from the idle screen and confirm the Program line accepts Enter.
- LOGO! Soft Comfort — connect LOGO! Soft Comfort V8.x or V8.4 to the same base over Ethernet, go to Tools → Access Control, and confirm the right-hand pane shows the TDE's IP as Admin.
- Read a parameter from the TDE: ESC → Program → Parameter — the parameter VM area should now open, confirming the TDE has RW rights to the base's variable memory.
- Edit a message text in the base circuit, write back, and confirm the change is visible on the TDE's message screen within one polling cycle (< 1 s).
| Check | Pass criterion |
|---|---|
| Idle screen status line | Shows two-arrow Ethernet icon |
| Setup → LOGO! Selection | Non-zero IP, base FW version displayed |
| Setup → Access Level | Reads ADMIN not OPERATOR
|
| Program tab | Selectable, opens menu |
| Soft Comfort → Access Control | TDE listed as Admin |
Password Handling — Operator vs. Admin vs. LOGO! Base
Three independent passwords can be in play. Confusing them is the second most common reason a TDE refuses to accept an admin change.
| Password slot | Default | Stored in | Function |
|---|---|---|---|
| LOGO! base access password | LOGO |
LOGO! 0BA8 base non-volatile | Authorizes writes from any client (TDE, Soft Comfort, HMI, PLC) |
| TDE local access level | Operator | TDE non-volatile | Determines which TDE menus are interactive |
| LOGO! program protection | None | LOGO! 0BA8 base non-volatile | Separate circuit-program read/write protection |
The TDE's Switch to Admin command does two things: (1) it sets the TDE's local access level to Admin, and (2) it transmits the LOGO! base password to the base so the base authorises future writes. If only (1) succeeds — because the link dropped mid-transaction — the TDE will look as if it switched but the base will continue to reject every subsequent write. Always re-confirm admin status in LOGO! Soft Comfort.
Common Variants and Edge Cases
TDE Used With LOGO! CMR2020 / CMR2040
If a LOGO! CMR (4G/3G or Ethernet) sits between the TDE and the base, the CMR performs NAT and the TDE must point to the internal IP of the LOGO! base, not the CMR's external IP. The TDE does not support NAT traversal; it can only address its peer directly.
Multiple TDEs on the Same Base
LOGO! 0BA8 / FS04 supports up to 8 TDEs simultaneously per base. Each TDE must have a unique IP. The base's access-control table is sized to that count; configuring a ninth TDE pushes the oldest entry out silently, which can also surface as FAILED TO SUBMIT on that displaced unit.
LOGO!Soft Comfort Online — Locked Base
If LOGO! Soft Comfort is online and holds the base in STOP for a download, the TDE will see the base as admin-occupied and any admin write will return FAILED TO SUBMIT. Disconnect Soft Comfort, cycle the base, retry from the TDE.
TDE Firmware Older than Base Firmware
Pairing a TDE on FW 1.04.x with a 0BA8 base on FW 8.4 may succeed for read but fail for the access-level write because the S7 opcode for "set access level" was extended. Update the TDE firmware via the LOGO! base's web server (Tools → Firmware Update) to match or exceed the base version.
Power-on Sequence
The TDE holds its network configuration in non-volatile memory but performs the link test on every power-up. If the LOGO! base is powered after the TDE, the TDE may complete its self-test before the base is on the wire. Power-cycle the TDE after the base is fully booted (all LEDs steady) and the link will re-establish on the next attempt.
Diagnostic Flowchart
Troubleshooting Matrix
| Symptom on TDE | Likely cause | Corrective action |
|---|---|---|
NO LINK on idle screen |
Cable/port fault | Replace patch cable, try another switch port |
FAILED TO SUBMIT immediately |
LOGO! Selection empty or wrong | Setup → LOGO! Selection → enter base IP |
| Password prompt never appears | TDE cannot reach base | Same as above — link issue, not auth issue |
| Prompt appears, error after entry | Wrong base password | Use LOGO default, or change via Soft Comfort |
| Admin granted, lost after power cycle | Non-volatile write blocked by base | Update base FW; check write-protect DIP on base |
| Multiple TDEs, only one fails | Base access table full (>8) | Remove unused TDEs from base access list |
| Admin granted but Program still greyed out | TDE local level did not update | Cycle TDE power after admin switch |
Standards and Reference Documents
- Siemens LOGO! 0BA8 System Manual, Edition 07/2016 — covers TDE commissioning, network setup, access levels. Available from the Siemens Industry Online Support portal.
- Siemens LOGO! 0BA8 FS04 manual supplement — updated TDE behaviour including the access-control table size and the post-FW 8.x opcode set. Search entry ID 109741041 in the Siemens support portal.
- LOGO! product family page — LOGO! logic module overview, including the TDE datasheet and current firmware downloads.
- LOGO! Soft Comfort V8.4 Online Help — describes the Access Control dialog used to verify TDE admin rights from a PC.
Why does the LOGO! TDE show "Failed to submit" with no password prompt when I press "Switch to Admin"?
The TDE could not establish a TCP session with the LOGO! 0BA8 base before the write was issued. Open Setup → LOGO! Selection on the TDE, enter the IP of the base (default 192.168.0.10), confirm the base responds, then retry. The TDE never asks for the LOGO! password until the link is healthy.
What is the default LOGO! base password that the TDE expects on admin login?
The factory default is the four-character string LOGO (case-sensitive, no leading/trailing spaces). Change it from LOGO! Soft Comfort under Tools → Access Control → Change Password; the new value propagates to the TDE on the next admin write.
How many LOGO! TDEs can a single LOGO! 0BA8 base support?
LOGO! 0BA8 / FS04 supports up to 8 TDEs concurrently. The base maintains an access-control table of 8 entries; a ninth TDE causes the oldest entry to be evicted silently, which can manifest as the new TDE being unable to complete an admin write.
Do I need LOGO! Soft Comfort to enable admin on the TDE?
No. The TDE can switch to admin on its own once the Ethernet link to the base is established and the correct base password is entered. Soft Comfort is only required to verify the admin state remotely or to change the base password.
My TDE says "ADMIN" but the Program tab is still greyed out. Why?
The TDE's local access-level variable and the base's server-side authorization are two separate states. If the base rejected the write but the TDE cached the local flag, the TDE will display ADMIN but refuse program edits. Cycle TDE power, confirm the link is live (idle-screen Ethernet icon), and re-issue the admin switch.