WinCC 7.0 SP3 Alarm Print: Fixing Failed to Print Empty Document

1. Problem Statement: "Failed to Print Empty Document" in WinCC 7.0 SP3 Alarm Logging

When configuring automatic alarm logging on WinCC 7.0 SP3 (part of the SIMATIC WinCC V7 product line), engineers frequently encounter the runtime error "Failed to print empty document" immediately after activating WinCC Runtime, even before any process alarm has occurred. A secondary symptom is that the Printer column in the print job list is blank, while a downstream alarm event triggers no printout at all. The same fault is reproduced when the operator tries to print a single alarm acknowledgement slip on demand.

The error is independent of the HMI station. It appears whether the operator has configured the printer on the local LPT1 port, a shared Windows network printer, or a generic text-only driver. The error is generated by the WinCC Alarm Logging editor, not by the operating system print spooler, which is why printer self-tests from Microsoft Word or Excel succeed while WinCC reports an empty document.

This article documents the root cause, the four configuration layers that must all be correct, and a verified step-by-step procedure to make automatic alarm printing work on WinCC 7.0 SP3 with Report Designer.

2. WinCC V7 Alarm Logging Print Architecture

WinCC Alarm Logging decouples the alarm event pipeline from the physical printer through two distinct objects:

• Print job: a logical entry inside Alarm Logging that defines when to print (trigger), where to print (printer / file / LPT port), and which layout to use.
• Report Designer layout: an XML/RDL file stored in the project that defines what to print (columns, header, footer, page setup, sort order).

WinCC 7.0 SP3 ships with a set of pre-defined print jobs created automatically when a project is generated:

The data flow at runtime is:

Process Tag / Bit Message
      │
      ▼
Alarm Logging Engine ──► Triggers Print Job ──► Loads Layout from disk
                                                   │
                                                   ▼
                                          Report Designer Runtime
                                                   │
                                                   ▼
                                          Print Spooler (LPT1 / Network)
                                                   │
                                                   ▼
                                              Physical Printer

If any link in this chain is broken, the print job either silently does nothing or surfaces the "Failed to print empty document" pop-up at runtime activation. The root cause is therefore always in one or more of the following four configuration layers:

1. The print job trigger (section 5).
2. The printer destination column inside the print job (section 7).
3. The Report Designer layout assigned to the print job (section 6).
4. The Windows-level printer / LPT1 mapping (section 7).

3. Root Cause Analysis

Siemens documented the most common causes of the "Failed to print empty document" error in the SIOS FAQ How do you configure a print job for the automatic printing of messages in WinCC Alarm Logging? The mapping of symptom to root cause observed in field deployments is summarised below.

4. Prerequisites

Before touching the project configuration, validate the following prerequisites on the engineering station and on the runtime station (the two are usually identical for single-station projects):

1. WinCC 7.0 SP3 installed, including the Report Designer sub-component. Verify in Control Panel → Programs: the entry "SIMATIC WinCC Report Designer" must be present.
2. Microsoft Excel is not required, but a default Windows printer must be installed and able to print a Windows test page successfully.
3. For LPT1 attachment: a USB-to-parallel adapter with proper Windows driver (e.g. MosChip MCS7715) and a generic/text-only driver assigned to LPT1.
4. For network printing: the Windows user that runs WinCC Runtime must have Print rights on the network share. WinCC Runtime launched from the start menu runs in the interactive user session; WinCC Runtime launched as a service runs as LocalSystem and cannot print to user-mapped network shares.
5. Project file backup: copy the project folder (typically C:\Siemens\WinCC\<ProjectName>) before any modification.

5. Step-by-Step: Configure the Print Job in Alarm Logging

This section walks through the Alarm Logging configuration that turns the pre-defined print job into a working automatic printer.

5.1 Open Alarm Logging

1. Launch WinCC Explorer on the engineering station.
2. In the navigation tree, right-click Alarm Logging and select Open. The Alarm Logging editor opens in its own window.
3. In the Alarm Logging tree, expand Print Jobs. You will see the pre-defined print jobs listed in section 2.

5.2 Select the Correct Print Job

For automatic per-event alarm printing, the print job that must be edited is:

@Report Alarm Logging RT Message Sequence

Right-click this print job and choose Properties. The print job dialog opens with three configuration tabs: General, Trigger, Layout.

5.3 Configure the General Tab

5.4 Configure the Trigger Tab

The trigger defines when the print job fires. For "print alarms as they come", enable the following events:

5.5 Configure the Layout Tab

On the Layout tab, point the print job to its corresponding RDL file:

@Report Alarm Logging RT Message Sequence.rpl

This file lives under the project directory at:

<Project>\PRT\<Language>\ALG\RtSeq.rpl

If the field is empty or shows red, the binding is broken and section 6 must be performed.

6. Step-by-Step: Validate the Report Designer Layout

Even with the print job configured correctly, a corrupted or modified layout will produce the "Failed to print empty document" error. Validate the layout as follows:

6.1 Open the Layout in Report Designer

1. Close the Alarm Logging editor if open.
2. In WinCC Explorer, right-click Report Designer → Open.
3. Navigate to File → Open and browse to <Project>\PRT\<Language>\ALG\RtSeq.rpl.

6.2 Verify the Data Connection

The default layout uses a table connected to the alarm logging archive via the internal ODBC data source. Check the connection:

1. In Report Designer, click the table object inside the layout.
2. Open the table's properties (right-click → Properties).
3. Under Connection, confirm the data source is the alarm logging connection defined in the project (typically CC_ALG_<ProjectName>_<Lang>_RT).

6.3 Verify the Column Set

The table must reference at least the columns listed in the table below; otherwise the rendering engine will produce an empty document even when alarms exist.

6.4 Save and Re-Test

1. Save the layout (File → Save) and close Report Designer.
2. Confirm the file timestamp updated under <Project>\PRT\<Language>\ALG\.
3. Re-open the Alarm Logging print job and confirm the layout binding is still valid (Layout tab).

7. Step-by-Step: LPT1 and Network Printer Mapping

The most common reason the Printer column is blank in the print job dialog is that the WinCC engineer typed the literal text "LPT1" into the field but never configured the LPT1 port at the Windows level, or used NET USE LPT1 inside a different Windows session. Both must be correct for the LPT1 destination to work.

7.1 Configure the LPT1 Port at Windows Level

1. Open Control Panel → Devices and Printers.
2. Click Add a printer → The printer that I want isn't listed.
3. Choose Add a local printer or network printer with manual settings.
4. Select Use an existing port and pick LPT1 (Printer Port).
5. Select the driver Generic / Text Only (recommended for alarm logging).
6. Name the printer WinCC_Alarm_LPT1.
7. Print a Windows test page and confirm physical output. If the test page prints, the OS layer is correct.

7.2 Map a Network Printer to LPT1 with NET USE

If the physical printer is on the network and the application requires an LPT1 address, redirect the share to LPT1:

NET USE LPT1 \\SERVERNAME\PRINTERSHARE /PERSISTENT:YES

Critical points:

• Execute the command in the same Windows session in which WinCC Runtime will run.
• If WinCC Runtime starts as a service (via WinCC RT Start configured as "Auto start" with the WinCC service mode), the NET USE must be performed in the service account session, not the interactive user session. For service mode, prefer the direct UNC path (\\SERVERNAME\PRINTERSHARE) in the print job Printer field.
• To make NET USE persistent across reboots, store the credentials once with cmdkey /add:SERVERNAME /user:DOMAIN\USER /pass:**** before the NET USE.

7.3 Verify the LPT1 Mapping

From the same Windows session that will launch WinCC Runtime, type:

DIR LPT1

If the device is mapped, Windows displays the spool queue contents. If not mapped, Windows returns "The system cannot find the path specified".

7.4 Type the Printer Destination in the Print Job

In the print job General tab, set Printer to exactly:

• LPT1 — when the printer is configured under Windows on the LPT1 port.
• WinCC_Alarm_LPT1 — when the printer name (as registered in Windows) is used.
• \\SERVERNAME\PRINTERSHARE — direct UNC path, recommended for service mode.
• FILE — print to PDF/text file. Useful for verifying the layout without physical printer hardware.

8. Runtime Verification

After completing sections 5–7, validate the configuration end-to-end:

1. In WinCC Explorer, click Activate on the toolbar.
2. Confirm no "Failed to print empty document" pop-up appears at runtime start. If it still appears, return to section 5 and disable the Runtime start trigger, or to section 6 to repair the layout.
3. Trigger a test alarm. Use the WinCC internal tag simulation tool or force the underlying PLC bit for one second. The alarm should appear in the Alarm Logging runtime window and be printed on the configured destination within 1–2 seconds.
4. Acknowledge the alarm. If the print job is configured to print on acknowledgement, a second printout should appear.
5. Open the spool queue on the target printer and confirm the WinCC job is present and released.

8.1 Capturing Diagnostic Output

WinCC Alarm Logging writes print-job diagnostic information into the project log directory:

<Project>\Diagnostics\AlarmLogging\<Timestamp>_AlarmLogDoc.prt

If printing still fails, open the most recent .prt file to inspect the actual layout output that Report Designer attempted to render. An empty file confirms the layout is firing before any data is available.

9. Extended Troubleshooting Matrix

The following matrix maps additional error messages observed on WinCC 7.0 SP3 alarm logging deployments to their likely cause and remediation. Apply the rows in order; each row supersedes the previous one if the symptom matches.

10. Print Job Parameter Reference

For future maintenance, the canonical mapping between Alarm Logging dialog fields, internal WinCC parameters, and runtime file outputs is shown below.

11. Best Practices for Production Deployments

1. Disable the "Runtime start" trigger on every print job that uses an event-driven layout. This single setting eliminates the majority of "Failed to print empty document" pop-ups at RT activation.
2. Use the direct UNC path (\\SERVER\SHARE) instead of NET USE LPT1 for WinCC servers running as a Windows service. NET USE mappings live in the user session that created them and disappear when the user logs off.
3. Always use the Generic / Text Only driver for alarm printing. Vendor-specific drivers (HP, Brother, etc.) inject page setup, headers and footers that corrupt the alarm layout.
4. Test with file output first. Set the print job destination to FILE with a fixed path, activate runtime, trigger alarms, and inspect the file. This isolates layout problems from spooler problems.
5. Version-control the RPL files. Treat RtSeq.rpl, RtList.rpl, and the other ALG RPL files as project source; check them into the same SCM (Subversion / Git / TFS) as the rest of the WinCC project. A layout regression after a project import is the second most common cause of empty-document errors.
6. Document the print job configuration inside the project documentation. Print job configuration is not exported by the WinCC Document Station by default and is lost if the project is rebuilt from a project backup.
7. Regenerate client packages after every change to a print job or layout. WinCC Clients do not pull print job changes from the server automatically; they need a fresh package.
8. Avoid mixing LPT1 and TCP/IP-attached printers on the same WinCC station. LPT1 is single-threaded; long print jobs will block alarm event handling and create alarm floods.

12. Frequently Asked Questions