OPC datasocket write problem

I have a main while loop (10sec timer)with heavy image analysis, and another while loop(0.1sec timer) that simply writes the resulting single number from the first loop into a OPC server via datasocket write function.

While it does work, the resulting datalog shows random 0's or huge numbers included once in a while.

(almost everytime the main loop is processing)

It seems like when the main loop is ongoing the second loop stutters and misfires.  

How can I keep my data stream clean of these errors?

Thanks