T 0030/21 (File system on a programmable logic controller/SIEMENS AG) of 12.10.2023

Summary of Facts and Submissions

I. The appellant (applicant) appealed against the examining division's decision refusing European patent application No. 11862283.6. That application was filed as international application PCT/US2011/030907 (published as WO 2012/134491 A1) with a filing date of 1 April 2011.

II. The documents cited in the contested decision included:

D1 US 2006/0190106 A1, published on 24 August 2006

D3 WO 02/31608 A2, published on 18 April 2002

III. The examining division decided among other things that the subject-matter of the independent claims of the main request and of each of the first to third auxiliary requests lacked an inventive step when starting from document D1. For the second and third auxiliary requests the examining division combined documents D1 and D3.

IV. In its statement of grounds of appeal, the appellant requested that the contested decision be set aside and that a patent be granted on the basis of the main request or one of the first to third auxiliary requests, all requests as considered in the contested decision and resubmitted with the grounds of appeal.

V. In a communication under Article 15(1) RPBA 2020 the board expressed among other things its provisional opinion that the subject-matter of claim 1 of all requests lacked inventive step. Moreover, claim 1 of the main request appeared to infringe Articles 84 and

123(2) EPC, and claim 1 of the third auxiliary request appeared to infringe Article 123(2) EPC.

VI. By letter of 12 September 2023, the appellant submitted a main request and a first auxiliary request. The appellant indicated that if the main request were to be admitted, it would replace all previous requests.

VII. Oral proceedings were held as scheduled and the appellant was heard on relevant issues. At the end of the oral proceedings, the Chair announced the board's decision.

VIII. The appellant's final requests were that the decision under appeal be set aside and that a patent be granted on the basis of the main request or the first auxiliary request, both requests filed by letter of 12 September 2023.

IX. Claim 1 of the main request reads as follows (itemisation of the features has been added by the board):

[a] "A programmable logic controller comprising:

[b] a controller module;

[c] a persistent file system module coupled to the controller module and adapted to persistently store archive data files, wherein a data archive file is in a user application format in a comma separate value (CSV) MIME type format, ASCII text, HTML or XML format;

[d] a memory module that stores binary data coupled to the controller module;

[e] a web server module coupled to the file system module and adapted to output a web page listing archive files stored in the persistent file system module; and

[f] a user program module that triggers a transfer operation including converting and writing binary data to the persistent file system module and stores instructions adapted to be executed by the controller module, the instructions including:

[g] creating an archive file in a user application format in the file system module;

[h] converting binary data stored in the memory module to the user application format of the archive file when a trigger condition for triggering the converting has been satisfied,

[i] the trigger condition being a user defined condition that is used to start the transfer steps,

[j] wherein the receiving and storing of binary data in the memory module continues while converting previously received and stored binary data; and

[k] storing the converted binary data as an entry in the archive file in the persistent file system module and

[l] receiving a request for a listing of archive files from a browser application and

[m] presenting a webpage listing the archive files in response to the request for a listing of the archive files."

X. Claim 1 of the first auxiliary request differs from the main request in that it adds the following text at the end of claim 1:

"on a host computer accessing an IP address and specific data archive web page stored within the file system module"

XI. The appellant's arguments relevant to the present decision are discussed in detail below.

Reasons for the Decision

1. The application relates to a file system for manipulating and accessing data on programmable logic controllers (PLCs), also known as industrial controllers. Raw binary data in a PLC may originate as electrical signals and/or process data from the application controlled by the PLC, and access to these data may require a proprietary external application. The invention proposes a web browser-accessible file system for accessing the data in a PLC (see description as published, page 1).

Admissibility of the requests under Article 13(2) RPBA 2020

2. Under Article 13(2) RPBA 2020 any amendment to a party's appeal case made after notification of a summons to oral proceedings shall, in principle, not be taken into account unless there are exceptional circumstances, which have been justified with cogent reasons by the party concerned.

3. The sets of claims according to the main request and the first auxiliary request were a response to objections under Articles 123(2) and 84 EPC raised for the first time in the board's preliminary opinion (see points V. and VI. above). The amendments made in the main request and the first auxiliary request address these fresh objections.

As this was the appellant's first opportunity to address these fresh objections, the board considers that there are exceptional circumstances (see decision T 2351/17, point 2 of the reasons and the further decisions cited in the Case Law of the Boards of Appeal of the EPO, 10th edition 2022, V.A.4.5.5 a)) which justify admitting the newly filed requests into the appeal proceedings under Article 13(2) RPBA 2020. Consequently, the board admits the main request and the first auxiliary request into the appeal proceedings.

Main request

4. Inventive step

4.1 The examining division considered that document D1 was a suitable starting point for assessing inventive step.

4.1.1 The appellant argued that document D1 was not a suitable starting point for assessing inventive step as it did not have the same purpose and effect as the invention and did not mention a similar technical problem (statement of grounds of appeal, page 3, first and second paragraphs).

4.1.2 The board is not convinced by this argument as document D1 relates to storing measured data from devices controlled by a PLC in files which are accessed via a web server. Consequently, document D1 relates to an overall problem that is very similar to the problem addressed by the application at issue (see point 1. above). Consequently, the board agrees with the examining division that document D1 is a suitable starting point for assessing inventive step.

4.2 The appellant argued that the examining division had misinterpreted document D1 and erroneously combined different embodiments for its novelty analysis (see statement of grounds of appeal, page 3, last paragraph to page 4, second paragraph). Figure 7 of D1 disclosed a different PLC from that disclosed in Figures 1 to 6 of D1. Consequently, the disclosure of Figure 7 could not be combined with the disclosure of the other figures for a novelty analysis.

4.2.1 The board agrees with the examining division's view that Figure 7 of document D1 illustrates another use of the industrial controller illustrated in Figures 1 and 2, for example. Figure 7 discloses how a remote client can access the files stored in the PLC disclosed in Figures 1 and 2. Neither Figure 7 nor the related paragraphs [0034] and [0035] of the description disclose anything that indicates an alternative embodiment from the industrial controllers disclosed in Figures 1 and 2, for example. Consequently, the board is not convinced by the appellant's argument.

4.3 The appellant agreed that document D1 disclosed features a, b and d of claim 1 (see point IX. above for the itemisation of the claim features). However, features c, e and g to m of claim 1 were not disclosed. Document D1 did not disclose a persistent file system as the files (data) were stored in RAM memory (see paragraphs [0027] and [0028]: "the file system services 46 reside and execute on a random access memory (RAM) residing on the industrial controller 40").

According to the appellant, document D1 did not disclose any conversion of data into a user application format or a user-defined trigger condition for starting the data transfer steps. Rather, it disclosed in paragraph [0035] periodically downloading measured and trend data to a data warehouse, which did not correspond to the user-defined trigger condition according to feature i. Feature j of claim 1 specified that there was continuous receiving and storing of binary data during the data conversion. Consequently,

the periodic transfer of data disclosed in document D1 and the trigger in claim 1 were completely different.

Moreover, paragraph [0035] of document D1 disclosed storing data outside the file system, which did not correspond to feature k. D1 also failed to disclose a request for a web page listing archive files and presenting such a web page as specified in features l and m. Rather, it disclosed in paragraph [0034] that a client application communicated over the internet with the file system to select a ladder program for execution on the PLC.

4.3.1 Regarding the obviousness of the distinguishing features identified by the appellant, the appellant argued that the user-defined trigger condition started the data transfer and data conversion. Data conversion was a "further" technical effect. Moreover, regarding features i, l and m, the appellant argued that the important feature was that the web page provided the capability to access files managed by the file system module in view of the conversion step at feature h and the creation of the archive file format at feature g of claim 1. The presentation of the web page therefore was technical pursuant to the case law, since the web page itself was displayed not for its cognitive content but as an access point for manipulating archive files that were not displayable in a user application.

4.3.2 According to the appellant, the distinguishing features c, e and g to m of claim 1 together achieved the technical effect of allowing a PLC to be interrogated by means of a web page user interface in order to see archive data files "relating to the running of the PLC". The conversion allowed "data to be seen in the native language of a user application on a web page". Consequently, the user application was able to carry out the interrogation. This represented an improvement on existing technologies, in which there was no ability to interrogate the PLC using a user application and a proprietary application was required to retrieve data (see point 1. above).

The objective technical problem was how to interrogate a PLC without resorting to proprietary applications. The solution was inventive since D1 was concerned not with interrogating the PLC but with RAM capacity issues. There were no non-technical user requirements with regard to the request for and subsequent presentation of a web page listing archive files. Document D1 did not provide a file listing in a format readable by a web browser. Consequently, the subject-matter of claim 1 involved an inventive step.

4.4 In accordance with the problem-solution approach, the board first determines which features of claim 1 are disclosed by document D1.

4.4.1 Document D1 (Figure 7, reference signs 132 and 134) discloses a PLC with a controller module. D1 also discloses a memory module storing binary data (such as logged data) in RAM memory (see Figure 1, reference signs 20 and 34; paragraph [0027]). Consequently, document D1 discloses features a, b and d of claim 1.

4.4.2 Document D1 (paragraph [0022]) discloses that the file system provides an interface to non-volatile storage devices such as hard drives or flash cards. The appellant cited paragraph [0028] of D1, which discloses that the "file system services [...] reside and execute on a" RAM memory. The board construes this passage as disclosing that the software for managing the file system executes in RAM memory. This interpretation of paragraph [0028] is entirely consistent with the disclosure in paragraph [0027], which discloses storing new temperature data that represent continuous measurements in a file to avoid the RAM memory capacity being reached. If the files were stored solely in RAM memory (as alleged by the appellant), then storing the data in a file could not solve any RAM memory capacity problem. Paragraph [0027] also discloses storing the file "in a separate memory device from the memory on which the application program executes", e.g. a non-volatile memory device residing on the PLC as disclosed in D1, paragraphs [0010] and [0022]. In view of the above, the board is convinced that document D1 discloses a persistent file system as specified in the first part of feature c of claim 1.

The second part of feature c specifies that an archive file is in a user application format. The board agrees with the appellant that D1 does not disclose files stored in a user application format.

4.4.3 In the board's view, document D1 discloses a web server (Figure 7, reference sign 146) coupled to the file system on the PLC (Figure 7, reference sign 138), i.e. the first part of feature e of claim 1. Moreover, the board considers that document D1 (paragraph [0027], "application program", and Figure 1, reference signs 20, 24 and 26) discloses a user program module that writes binary data to a persistent file and stores instructions adapted to be executed by the controller module (see feature f of claim 1). Finally, paragraph [0027] of document D1 discloses storing binary data in a persistent file (see feature k).

4.4.4 In view of the above, the board concludes that the subject-matter of claim 1 differs from the disclosure of document D1 on account of the following distinguishing features:

DF1 A data archive file is in a user application format in a comma separate value (CSV) MIME type format, ASCII text, HTML or XML format (see feature c).

DF2 The user program module comprises instructions to create an archive file in a user application format in the file system module and to store the binary data in the converted format as an entry in an archive file (see features g and k).

DF3 The user program module comprises instructions to convert binary data stored in the memory to the user application format of the archive file when a trigger condition for triggering the conversion has been satisfied (see features f and h).

DF4 The trigger condition is a user-defined condition that is used to start the transfer steps (see feature i).

DF5 The receiving and storing of binary data in the memory module continues during the conversion of previously received and stored binary data (see feature j).

DF6 The web server module is adapted to output a web page listing archive files stored in the persistent file system module (see the second part of feature e).

DF7 The user program module comprises instructions to receive a request for a listing of archive files from a browser application and to present a web page listing the archive files in response to the request for a listing of the archive files (see features l and m).

4.5 In the following, the board applies the problem-solution approach separately to the following two groups of distinguishing features - DF1 to DF5, and DF6 to DF7 - since these two groups of features do not interact to achieve a synergistic effect.

4.6 In the board's view, the distinguishing features DF1 to DF5 provide a data file in one of the standard user application formats specified in feature c of claim 1 (e.g. HTML or XML format; see also the description of the application at issue, page 6, second paragraph). Storing data in files in these standard user application formats enables access to data in the files by means of user applications that are able to read these standard file formats. However, claim 1 does not specify any access to data in an archive file, and so there can be at most only a potential for a technical effect of data access by means of standard user applications. The board has doubts that this potential effect constitutes a "further" technical effect as per decision G 1/19, points 94 to 96. Even if it were accepted, for the appellant's benefit, that the effect of enabling access by means of user applications that are able to read certain standard file formats constituted a "further" technical effect, it was straightforward to use conversion to a standard user application format when solving the problem of enabling access to stored data by commonplace user applications.

Moreover, since D1 (paragraph [0027]) discloses that temperature measurement data are received continuously and the PLC consequently needs to be able to deal itself with incoming measurement data on a continuous basis (e.g. to avoid memory issues), and the skilled person understands that measurement data are received in a proprietary format (see also point 1. above), it was a straightforward option to use some kind of trigger condition to start the data conversion.

Regarding the distinguishing feature DF4, the board considers that the trigger condition being "user defined" does not achieve any technical effect. In this context the board notes that claim 1 specifies neither the "user" nor the condition in any detail. As discussed at the oral proceedings before the board, the description of the current application discloses on page 7, first paragraph, that "any practicable trigger condition may be used to initiate the transfer", including the memory having been filled. Since document D1 (paragraph [0027]) already discloses writing measurement data to a file to avoid RAM capacity issues, the distinguishing feature DF4 was in any case obvious when starting from document D1 since the skilled person could and would use a condition to start the transfer and conversion of data to avoid a memory capacity problem, for example. The appellant's argument that paragraph [0035] of D1 disclosed periodically downloading data into a data warehouse is not relevant since claim 1 does not relate to downloading data into a data warehouse.

The distinguishing feature DF5 essentially specifies that the storing of received measurement data in the memory module and the transfer and conversion of data stored previously in the memory module to a file are performed concurrently. As the examining division correctly observed, document D1 (paragraph [0027]) discloses continuous temperature measurements, so measurement data continuously arrive in the memory module. Since the process of receiving data is continuous, concurrently transferring and converting the incoming data to a file was a straightforward implementation option.

Consequently, the distinguishing features DF1 to DF5 cannot provide a basis for acknowledging an inventive step.

4.6.1 The distinguishing features DF6 and DF7 enable web access to a listing of files being stored on the PLC in a user application format.

Regarding features l and m, the examining division essentially argued in point 12.4 of its decision that the possibility of requesting a listing of archive files and the subsequent presentation of this listing on a web page to the requesting user was a non-technical user requirement, and the board agrees.

The board notes that the fact that the archive files store data in a certain format does not play any role for the presentation of the listing on a web page since the web page is merely used to present a listing of the files, i.e the data stored in the files is not presented. Moreover, claim 1 does not specify any interaction with this listing such as a selection and downloading of a selected archive file. Consequently, the appellant's arguments relating to (1) alleged advantages of the archive file format in the context of features l and m or (2) any technical effect achieved by interacting with the listing are not supported by the wording of claim 1. Consequently, the board concludes that features l and m use the web access to the file system on the PLC (see D1, Figure 7 and paragraph [0034]) in a straightforward manner to implement the non-technical user requirement of presenting a listing of the archive files on the PLC on the client. Consequently, the distinguishing features DF6 and DF7 are obvious.

4.7 In view of the above, claim 1 of the main request lacks an inventive step (Article 56 EPC) over document D1.

First auxiliary request

5. Claim 1 of the first auxiliary request adds the following feature at the end of claim 1 of the main request:

"on a host computer accessing an IP address and specific data archive web page stored within the file system module"

6. Inventive step

6.1 The feature added by the first auxiliary request was already present in the former second auxiliary request that was considered in the decision under appeal. Regarding this feature, the examining division considered that document D1 (Figure 7 and paragraph [0034]) disclosed a web browser running on a host and accessing the PLC via a web service. This web service access implied using an IP address and accessing a web page with contents according to user requirements. D1 did not disclose how the web service was implemented or where the web page was stored, but document D3 (Figures 1 and 2; page 7, line 21 to page 8, line 15) disclosed storing web pages on the PLC. Consequently, the examining division considered the feature added by the former second auxiliary request to be obvious.

6.2 The appellant argued that paragraph [0034] of document D1 disclosed that the client application was connected to the internet via a web service and a web browser, so that the client application was able to select a ladder program for execution by the PLC. However, document D1 did not mention any web page storage or access. Moreover, combining documents D1 and D3 would at best result in a web page stored in the file system accessible by the web service to allow the client application to select ladder logic files and access the logged measured and trend data, which would need to be displayed on the same web page with associated display instructions. The claimed invention did not require any such instructions since it used a user application format. Consequently, the subject-matter of claim 1 was inventive.

6.3 The board agrees with the examining division's arguments. The first auxiliary request essentially adds that a specific web page is accessed by a browser in the usual manner. In this regard, the board also considers that storing web pages in the file system (and thus on the PLC disclosed in D1) for access by a web server was well known at the filing date. A specific "data archive" web page being accessed was within the skilled person's routine development skills at the filing date. In particular, the skilled person was aware that requesting a web page typically meant accessing a specific web page via an address (URL). Consequently, it was straightforward to access a specific data archive web page when a request for listing archive data files was required.

Moreover, claim 1 specifies that the data stored in an archive file is in a user application format. This does not imply that the web page listing of the archive files also uses a user application format. However, since, according to feature c of claim 1, HTML is a user application format and since web pages in HTML format, were notorious at the filing date, it was in any case obvious for the skilled person to provide a web page listing the archive files in HTML format.

In view of the above, the appellant's arguments are not convincing and the subject-matter of claim 1 of the first auxiliary request lacks inventive step (Article 56 EPC) over document D1 in view of document D3.

7. Since none of the appellant's requests can form the basis for the grant of a patent, the appeal is to be dismissed.

Order

For these reasons it is decided that:

The appeal is dismissed.