Siemens Coros OP15 OP37 Panel Program Upload with ComText

Overview: Recovering Programs from Legacy Siemens Coros OP Panels

The Siemens Coros OP family (OP5, OP15, OP15-B, OP20, OP25, OP27, OP37, OP393, OP397) is a generation of text- and graphics-capable operator panels that pre-dates today's SIMATIC HMI Panels portfolio. A persistent service problem with these panels is the absence of source-level project files ("no program on file") combined with a working unit in the field. Engineers routinely face a bricked spare or replacement panel with no ProTool/ProTool/Lite source available and only the original Siemens Programming Device (PG) or a serial cable.

This reference consolidates the upload, transfer, and recovery paths for every Coros generation, contrasts ComText v3.1 against ProTool/ProSave, documents the Error $081 cable fault on the OP15-B, and ties the workflow to modern migration targets such as SIMATIC HMI Unified Panels.

Coros OP Panel Families and Upload Capability Matrix

The following matrix maps every Coros panel to the tools that can read or write its project. Use it to identify which tool applies to the unit on the bench before opening any software.

Source for tool coverage: Siemens support note "What are the functional differences between the different SIMATIC panels?" (ID 40227286). Note that the Coros OP family is described under the "Operator panels for hazardous areas / older text and graphics panels" line.

ComText v3.1 — The DOS-Based Upload Tool for Coros Text Panels

ComText is a legacy Siemens DOS utility that ships (or shipped) with the ProTool CD set and is the only tool that performs a true bidirectional transfer on OP5, OP15, OP15-B, OP20, and OP397. ComText v3.1 supports the following devices:

• TD10
• TD20
• OP5
• OP15 / OP15-B
• OP20
• OP397

ComText treats the project file as a flat text/ASCII configuration rather than as a compiled runtime image. Round-tripping (upload → edit → download) is therefore possible without a decompiler. This is the answer to the classic service question: "How do I get a program out of a working OP15 when I have no ProTool source on file?"

ComText Upload Procedure (OP5/OP15/OP20/OP397)

1. Connect the Siemens PG (PG 7xx, PG 7xxM, or Field PG) to the OP panel using the original Siemens serial cable (6ES5 734-1BD20 or equivalent; see cable section below).
2. Power the OP panel and enter transfer mode via the panel's built-in setup menu (typically MENU → SETUP → TRANSFER). The OP15 displays the active serial parameters (baud, parity, node address).
3. Start ComText v3.1 on the PG in DOS or a DOS window.
4. Select File → Upload and choose the target device (OP5 / OP15 / OP20 / OP397).
5. Confirm the serial parameters match (default 9600,8,N,1 for OP15-B).
6. The project is written to the PG as an editable .CTX file.
7. Open the .CTX in ComText or ProTool to make changes, then download with File → Download.

ProTool and ProSave — Compiled-Image Only

ProTool is the Windows-based successor that compiles the project on download. Think of the result as a "zip file" containing all screens, tags, alarm logs, and recipes in a single packed runtime image. This is intentional — compiled images run faster on the panel and protect the developer's IP.

ProSave — Backup and Restore

ProSave is included on the ProTool CD and performs two operations only:

• Backup (panel → PC): writes the compiled runtime image to a .PBA / .PSV file.
• Restore (PC → panel): writes that compiled image back to the panel.

ProTool Upload Procedure (Panel → PC, compiled only)

1. Open ProTool / ProTool/Lite on the engineering station.
2. Launch ProSave from the install directory (typically Start → SIMATIC → ProTool → ProSave).
3. Select the connection type (Serial / MPI / PROFIBUS / Ethernet depending on panel model).
4. Choose Backup and the destination directory.
5. Power the panel into transfer mode and start the transfer.
6. When complete, the panel displays "Transfer complete — restart".

If the goal is to edit the project, stop here and switch to ComText (for OP5/OP15/OP20/OP397) or accept that the source cannot be recovered (for OP25 / OP37 without an upload flag).

OP25: Upload Is Not Available

OP25 is a transitional panel: Siemens produced ProTool support, but the upload path was disabled at the firmware level. There is no ComText tool for OP25 and no ProTool menu item that produces an editable file. Any attempt to upload from an OP25 will fail with a transfer error or yield an unusable image.

Field recovery for OP25 is limited to:

• Locating the original .PBA / .PTP project file on the customer's engineering PC or a network share.
• Re-creating the screens from the running panel by hand if no source exists. Document every tag, alarm, and recipe before power-down.
• Replacing the OP25 with an OP27 (drop-in compatible in many cabinets) so that the next service event is recoverable.

OP27: Upload Returns

The OP27 generation re-introduced the upload capability that OP25 lacked. Upload on OP27 is conditional:

1. The original developer must have selected Project → Properties → Transfer → Enable Upload in ProTool at the time of the first download.
2. The same project file (or at least the upload metadata) must still exist on the engineering PC. ProTool needs the project skeleton to merge the uploaded runtime into.
3. The connection (serial, MPI, or PROFIBUS) must be configured identically.

If any of the three conditions is missing, the upload returns either nothing or a partial runtime that ProTool cannot open.

OP 393 III — Graphics-Capable Coros

The OP393 III is the graphics-capable successor to the OP37. The "Manual OP 393 III" is the operator and service reference that documents the upload procedure. The OP393 III uses ProTool (graphics) for development and supports source upload under the same conditions as OP27 (upload flag + matching engineering project on the PC). The OP393 III accepts the same serial cable family as the OP15-B but at higher default baud (19200,8,N,1).

MP370 — Source Upload with Two Conditions

The MP370 sits at the boundary between Coros and the modern WinCC flexible / TIA Portal era. It is the last panel where engineers routinely encountered "we lost the source, can we get it off the panel?" — and the last one that could sometimes answer "yes".

MP370 Upload Preconditions

Field practice: any MP370 that is downloaded with a CF card inserted and "Enable Upload" selected is recoverable. Any MP370 downloaded without the CF card or with the option disabled is not recoverable through the panel — only through the engineering PC's backup media.

Error $081 — PG-to-OP15-B Cable Fault

One of the recurring field faults reported on the OP15-B is Error $081 returned during a ComText v3.1 upload from a Siemens PG. Error $081 indicates a serial handshake or framing fault on the TTY / RS-232 link between the PG and the panel. The most common root cause is an incorrect cable pin layout, particularly on third-party or hand-built cables.

OP15-B Serial Connector Pinout (Siemens 6ES5 734-1BD20 cable)

Error $081 Diagnostic Steps

1. Verify the cable part number. Genuine Siemens cable is 6ES5 734-1BD20; any substitute must be a null-modem with full handshaking (not 3-wire).
2. Confirm the OP15-B is in transfer mode (setup menu, not normal operation).
3. Match baud rate: 9600,8,N,1 is the OP15-B factory default; older OP15 uses 4800,8,N,1.
4. Check that no other serial device (mouse, modem) is using COM1 / COM2 on the PG.
5. Run a loopback test on the PG COM port with a terminal emulator. If the loopback fails, replace the PG serial card.
6. If Error $081 persists, try the same transfer from a Field PG with the genuine Siemens cable before declaring the OP15-B faulty.

Pin Layout — PG to Coros OP Family Reference

Beyond the OP15-B cable above, the Coros family uses a small set of consistent serial conventions. The table below summarises what the engineer will see at the connector on each panel and what cable adapts the PG to it.

Choosing the Right Tool for the Job

Engineers reaching for "any tool that might upload the panel" should follow the decision tree below. The tree is intentionally short because the Coros generation leaves very few options.

1. Is the panel an OP5, OP15, OP15-B, OP20, OP397? → Use ComText v3.1. Result is editable.
2. Is the panel an OP27 or OP393 III? → Use ProTool. Result is editable only if the original download had "Enable Upload" set.
3. Is the panel an MP370 with the original CF card still in place? → Use WinCC flexible or ProTool upload. Result is editable only if "Enable Upload" was set.
4. Is the panel an OP25 or OP37 without upload flag? → Use ProSave to clone to a spare panel. Source recovery is impossible.

Field-Proven Recovery Workflow for an OP15 with No Source

This is the scenario the source describes: "The guy in charge of taking care of our Coros OP panels (15 & 37) went on to greener pastures. … I have one OP15 down now and no program on file." The correct sequence is:

1. Identify the working OP15 on the shop floor. Confirm the firmware version from the panel's diagnostic menu (HELP → VERSION).
2. Locate a Siemens PG with the original cable (6ES5 734-1BD20) and ComText v3.1 installed.
3. Power the working OP15 into transfer mode.
4. From ComText v3.1, perform an Upload to the PG.
5. Save the resulting .CTX file under a meaningful name (e.g. OP15_LINE3_2024.CTX).
6. Open the .CTX in ComText to verify the screens, tags, and recipes were captured.
7. For the OP15 that is down, install a replacement unit of the same type, place it in transfer mode, and download the saved .CTX with ComText.
8. Verify on the panel that every screen renders, every tag updates, and every alarm triggers before handing back to operations.

Repeat the same ComText upload for every OP15, OP20, and OP397 on site to build a library of editable backups. For OP37, fall back to ProSave and store the compiled image with a written description of what it contains — that is the only source the company will ever have.

Modern Migration: Replacing Coros with SIMATIC Unified Panels

The Coros family is end-of-life. Any new procurement should target the SIMATIC HMI Unified Panels range (4–12 inch displays), or the established SIMATIC HMI Comfort / Basic 2nd Generation line. The functional differences across the modern line are documented in Siemens Support entry 40227286, which covers Basic Panels 2nd Generation, Mobile Panels, Multi Panels, and Comfort Panels.

Migration notes:

• Source code: a Coros ProTool project must be re-authored in TIA Portal / WinCC Unified. There is no automatic converter. Plan a manual screen rewrite with tag-mapping documentation.
• Hardware: a Unified Comfort Panel of equivalent display size can usually be cut into the same cabinet cut-out with an adapter plate. Check the depth — Comfort and Unified Panels are deeper than OP15/OP25/OP37.
• Connection: convert the OP15-B TTY link to MPI / PROFINET on the Unified Panel. The PG cable 6ES5 734-1BD20 is not used on Unified hardware.
• Image deployment: use the SIMATIC HMI Panel Image tool, documented in Siemens Support entry 109746530, to install firmware on Comfort and Unified Panels. The same article covers Unified Comfort, Unified Basic, and Comfort Panel images.

Troubleshooting Matrix — Coros OP Upload Failures

Verification Checklist After Any Coros Upload

Once a backup or upload completes, run through this checklist before declaring the panel service-ready.

1. Power-cycle the panel and confirm it enters normal operation (not stuck in transfer mode).
2. Touch every screen and confirm it renders without missing text or graphics.
3. Force a tag write from the PLC and confirm the value updates on the panel.
4. Force a tag write from the panel (where allowed) and confirm the PLC sees it.
5. Trigger every alarm class and confirm the panel logs and acknowledges it.
6. Print or save a screen capture of the version screen (HELP → VERSION) for the maintenance file.
7. Store the .CTX / .PBA / .PSV file in the site's CMMS or version-controlled backup location with a date stamp and panel serial number.
8. Document the cable, baud, and node address actually used, so the next engineer does not start from zero.

FAQ