(Another!) Serial read problem in Firefly

Hi guys,

I'm communicating with a 3D printer via Grasshopper / Firefly (and eventually) Silkworm.

So far, I can quite happily send G-Code move commands to the printer  - which is a Leapfrog Creatr, based on Arduino Mega / RAMPS electronics - via the generic Serial Write command. 

I also want to get a return feed of information, which will basically tell me when the printhead has reached its destination (so normally sending the printer a code 'M114' will get it to return a string along the lines of :

X:100.00Y:15.00Z1.20E:0.00 Count X:100.00Y:15.00Z1.20E:0.00

ok

you can see this works in an arduino serial monitor window from the screenshot below.

Unfortunately I can't seem to get the generic "Serial Read" block to work for me in Grasshopper. (I do have the arduino serial monitor closed, and the "Hurray" message is displaying)

When I write a log file, the txt file does grow, but full of empty lines.

I'm stumped, really - there are lots of other people who have asked this question / had this problem, but unfortunately most of them never explained how they got it working when they did....

Thanks in advance

Fergal