No here are the citation from the law:
Operational Manual ENF 23, Section 6.4
6.2 Canadian business
The definition applies to both large and small businesses, and includes: ENF 23 Loss of permanent resident status
federally or provincially incorporated businesses which have an ongoing operation in Canada;
other enterprises that have an ongoing operation in Canada, are capable of generating revenue, are carried out in anticipation of profit and in which a majority of voting or ownership interests is held by Canadian citizens, permanent residents or Canadian businesses;
enterprises which have been created by the laws of Canada or a province.
Note: It does not include businesses that have been created primarily for the purpose of allowing a permanent resident to satisfy his or her residency obligation while residing outside of Canada R61(2).
6.4 Day
For the purpose of calculating the number of days to comply with the residency obligation in A28(2)(a), a day includes a full day or any part of a day that a permanent resident is physically present in Canada. Any part of a day spent in Canada, or otherwise in compliance with A28(2)(a), is to be counted as one full day for the purpose of calculating the 730 days in a five-year period.
6.5 Employment outside of Canada
The regulations enable permanent residents to comply with the residency obligations while working abroad, provided that:
they are under contract to, or are full-time employees of a Canadian business or in the public service, where the assignment is controlled from the head office of a Canadian business or public institution in Canada;
they are assigned on a full-time basis as a term of their employment or contract, to a position outside Canada with that business, an affiliated enterprise or a client;
they maintain a connection to a Canadian business;
the are assigned on a temporary basis to the work assignment; and
they will continue working for the employer, in Canada, after the assignment.
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=727&top=4
So according these definitions, even if you go for a temporary business trip as long as it is an official assignment it shall count to your PR status. But you need to have permanent contract with a Canadian company.