How do I get LabVIEW to handshake properly with my scales?

[damon]

I'm using a program written in labview that is used to calculate the center of mass of a 3-d object. We are using 3 scout II scales to take the mass readings. However when we run the program, the scales lose their readings or become rezeroed. Why is this happening?

[aderogba]

When you run MPB.vi by itself do you have the same behaviour?

[Spaz]

Your VI's did not load completely in my setup but I see two quick off the cuff possibilities...

1. That the boolean(s) (They are unassigned "?"'s when loaded in mine)wired to the cases that determine your device dependent commands (P or T for the serial write) are indeed false and you are actually sending the command to rezero the scale to it.

2.) The scale is sensing the loss of possible serial handshaking lines and performing some sort of boot process due to the serial port initializations repeatedly taking place in the while loop. It is typically not necessary to reinitialize your serial ports before each data transmission / reception and may be to your advantage to place them outside the while loop.