[R] set off error messages

[Mollet, Fabian]

Hello there!
 
I'm creacting a loop for(i in 1:n){...}within which I build a nls model at each iteration. for some of the values of i, the algoritm in the nls function doesn't converge or cannot find a solution and consequently an error message is produced, and so my loop is interupted. The errors don't really matter to me as all the other values might still be useful and therefore I want to ignore the errors, so that that the return of the models for which no solution is found should just be NA values, so that I get a value for every i. How can I turn off the error message and make return NA values instead?
 
Thanks in advance for your help...
 
Fabian