problem with DS18B20

I have tried the other 3 boards I have, and 2 of them does not work either.
I have tried a timing loop, and there are almost 1% in difference, between the board that work, and the board that not work.
/* board that not work

echo(0);
1222.878175000000055661
1224.138924999999971987
=undefined

/
/ board that work
echo(0);
7.64065
8.912875
=undefined

*/
CODE
clearInterval();
clearWatch();

print(getTime());
for(i=0;i<10000;i++);
print(getTime());
END CODE

/* board that not work
sensor
={"bus":{"pin":A0},"sCode":undefined}

7.34425
7.34925

*/

/* board that work
sensor
={"bus":{"pin":A0},"sCode":3530822130496018984}

9.21675
9.2449

The timing here are before, and after the require.
CODE
print(getTime());
var sensor = require("DS18B20").connect(ow);
print(getTime());
END CODE

Maybe it has something with the timing to do.