For a very safer side, may I know how many days I can maximum stay during my trip?
I don't want to take any risk with my residency status.
I largely concur in the thorough response by
@evdm and the following in particular.
In theory, your return date must therefore be no later than 181 days before 25 June, 2019 which would be 26 December, 2018 (Assuming you leave on March 1). This, because when you enter Canada you have to show to the officer that you will be able to satisfy your residency requirement for the remaining period of your first 5 years as a PR if they ask for it. In my opinion it would be cutting it close.
As for . . .
total 512 days I have spent in Canada so far. and my PR card is valid up to 11.08.2019.
The date your PR card is valid for is NOT RELEVANT. NOT RELEVANT.
Count how many days you have been in Canada since the date you landed and became a PR, until the date you leave. The start date, the date you landed, appears to be June 26, 2014. Count days in Canada from that day to the day you leave Canada.
Add to that the number of days there are left on the calendar between the date you leave and June 25, 2019, the day before the fifth year anniversary of the day you landed.
If that total is 730 days or more, you are in compliance with the PR Residency Obligation.
Then subtract the number of those days you will be abroad before June 26, 2019. As long as the total is still above 730 you are in compliance.
But if that total is less than, say, 900 days total, that is
cutting-it-close (that is spending less than half time in Canada, indicating you have not fully settled in Canada and tending to support
an inference you were outside Canada any dates which it is not for-sure you show you were in Canada), which could mean you are challenged about meeting the PR RO and would need to present substantive proof of your days in Canada. Remember, while the actual number of days you spend in Canada are important, decisions can be made based on the number of days you PROVE you were in Canada.
This forum is rife with tales of trial and tribulation, tales of woe even, for PRs who
cut-it-close. Many made it back to Canada in time, but faced long delays in getting a new PR card and the difficulties that can cause. More than a few ran into additional problems and failed to make it back to Canada in time. An accident or compelling situation that means having to stay abroad an extra three months, delaying a return past the date for staying in compliance, for example, is NOT likely to suffice as H&C reasons for waiving a breach of the PR RO . . . the PR had three other years to spend in Canada. (Many an IAD panel and Federal Court justice have emphasized that the reason for the very liberal PR RO is precisely to accommodate such things, to accommodate compelling circumstances in life, NOT to facilitate only partially living in Canada plus an emergency or such.)
Remember, just because a PR card is still valid does not guarantee the PR does not get reported when arriving at the Port-of-Entry into Canada. A PR in the first five years since landing who returns to Canada during the last two years of the first five years after an extended absence (many months or more) actually faces a significant risk of a Residency examination at the PoE.