Unluckily there is no way to give you an exact answer without reviewing the specifics of your system (which you will not want to share on Avvo, see a patent attorney in private). You would need to meet with a patent attorney to discuss all the details of your case to get a correct answer, and I would recommend meeting with a patent attorney anyways when filing a patent as the complexity of filing has been known to trip many a layperson (and even some attorneys).
That all being said, filing the two functions in a single patent would likely not do any harm. If the examiner at the United States Patent and Trademark Office determines that the functions should be broken down into two separate patents he/she will require you to make an election of which function you would like to pursue under that patent. Once the election is made, if you choose to, you can file a divisional application to obtain protection for the separate function. The only downsides might be cost and time to obtain protection for both functions. Although with that said, a patent attorney will be able to look over the details of your invention and will likely be able to tell you if there needs to be 2 separate patents filed.
Answering of your question is merely general advice and does not constitute legal advice. None of the statements or implications made by this answer creates an attorney-client relationship with the attorney answering the question. The statements made in this answer are not to be solely relied upon and you should meet with a competent attorney to discuss any concerns you may have regarding this answer.
This is a strategy call based on financial, logistic, and procedural considerations. Generally,I prefer to keep separate patents separate to prevent cross access during pendancy. However, that increases cost somewhat, so for small inventors the cost may be more important and lead to combining inventions, which also has some other advantages beyond the level of this forum.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
Generally my preference is to prepare one application that discloses the entire system, including subsystems. What you actually claim in that application depends on considerations such as budget, maturity of your technology and business, interactions with potential investors, and the like. As patent prosecution progresses, you may file continuation applications to pursue claims to other aspects that were disclosed in the initial application.
(949) 390-2717 - Of course there's more to it! Plus, we don't have an attorney-client relationship. This brief comment is for information only, and must not be relied upon as legal advice.
I agree with my colleagues. If the budget is limited right now, starting by filing one application, which properly discloses and claims both functions, may be the best choice. That would secure a filing date for both functions/inventive aspects. Whether the application should be split into two or more applications, on your own initiative or because the examiner requests it, can be determined at a later time, during prosecution.
This is general information only. For legal advice, based on your specific facts, an attorney needs to be hired first.
It looks like you are trying to draft your own patent application. That is a very dumb move. The question you have asked requires significant judgment and expertise, and there are many strategic implications arising from how you deal with this. You absolutely need to retain a patent lawyer to guide you---and not just a patent lawyer who specializes in prosecution of patent applications. In a situation like this, you also need guidance from a patent lawyer who is involved in litigation. You need advise on what approach will make it more likely that you will be successful when you attempt to enforce your patent in an infringement suit. The answer may vary depending on the nature of your system and its two functions. This primarily a litigation strategy decision, but it is also a decision which must be informed by experience of patent prosecution attorneys concerning when you can get away with claiming a single invention, or when you need to claim multiple inventions. These are complex matters and you cannot possibly handle these without retaining experienced patent counsel---indeed, you need a team involving patent prosecution and patent litigation counsel.
As others have suggested, I usually try to combine similar ideas and functions into a single patent to save initial costs and avoid potential prior art issues. I then try and claim the general distinct functions and ideas in the initial claim set. If needed, we elect to proceed with one function or idea and pursue the others in divisional applications.
There are different strategies about how to proceed with an application. Selecting the right one for your position would depend on the details of the invention. Things to think about are differences in operations within the system; structural differences; and the type of prior art for example. A patent attorney can help select the proper strategy for your particular invention. Many will give free consultations.
This answer is for general purposes only and does not establish an attorney-client relationship. Select and contact an attorney of your choice to further explore your options.