use a variable in a Test Stand pop up message

[lmd2]

I have a parallel model running 3 sockets, each test loops three times and each loop has a long cool down time and a message pop up for the operator to initiate the next loop. Because of the long cool down time often 2 or three of the samples are in 'cool down' at the same time, and when a message pop up appears on the scren "Press OK to start the next loop" - it isn't obvious to the user which of the samples is about to be energized. For safety considerations I need the message to dynamically read: "Press OK to start the next loop for sample #N" where N would be the socket number.
I think that I am on the right track, but am having syntax errors (or maybe my entire approach could be wrong(?))
I am trying to set the message expression for the message pop up using:
 "Press OK to start sample #" + RunState.TestSockets.MyIndex
MyIndex is a number, do I need to coerce it to a string, or am I trying to access the wrong varible altogether?
it might make more sense to display the UUT serial number associated with the execution thread, where would I access that variable?

TIA

lmd2

[Dennis_Knutson]

Yes, you have to convert to a string. Use:

Str(RunState.TestSockets.MyIndex)

[lmd2]

that did it, thanx a lot