Paul,

Many thanks for the prompt reply.

One further question, in the original code there was the command to WRITE the result
Code:
WRITE Bvar, WORD SetPoints(EditChannel)
Would I need to use a similar line to update the normtemp variable with the data received from the PC, or will
Code:
Hserin [DEC3 normtemp(0)]
Hserin [DEC3 normtemp(1)]
Hserin [DEC3 normtemp(2)]
Hserin [DEC3 normtemp(3)]
suffice.

Also I'll add Bruce's time out as suggested, but should I also have the PIC send something at the end to tell the PC to signify data recived ?