I am trying to use SignalExpress to acquire data
from multiple sources, and I created a user-defined step in LabVIEW 8
for SignalExpress to use. This VI acquires data from a thermistor that
has an infrared-RS232 (9 pin) adapter, which in turns plugs into an
RS232-USB converter cable (because my laptop does not have a 9-pin
RS232 port). However, when I try running the step, I am getting an
error in SignalExpress that says
Possible reason(s):
VISA: (Hex 0xBFFF006B) A framing error occurred during transfer
and
occasionally I also get an error message suggesting an I/O error. There
was one attempt at running my project when data was properly
transmitted every other time (my device outputs every three seconds),
so I'm kind of confused...
The VI itself works fine in LabVIEW;
I've never gotten any errors when I run it in LabVIEW. Following the
information I found in a forum search (this seems to be a very common
problem!) and a KB article,
I checked the port settings (baud rate, number of data bits, parity,
flow control, and number of stop bits) in MAX and what I specified in
my VI, and they match my device's port settings specs. In MAX, I also
performed a test panel and it seems to be transmitting something,
although when I select "ASCII" only (which is what my device outputs),
the reading is just a bunch of elipses and X's, which isn't what I
would expect, but then again I'm a student and don't have a lot of
experience with this stuff.
I'm not really sure what's going
on, if my VI seems to work perfectly in LabVIEW and problems arise only
when it's imported into SignalExpress. I wonder if the problem could be
noise due to a long cable (the infrared-RS232 adapter that I ordered
with the thermistor is several feet long) and/or a cheap RS232-USB
converter cable that I just bought at a local store. Or maybe there is too much EM radiation in my room (what kind of appliances would cause interference? Refrigerators? Stereo system?) As extra info, I
also programmed a kind of wait in my VI to not
read my selected COM port until Number of Bytes at Serial Port is more
than 0 (because this will be a continuosuly running step
in SignalExpress and there will only be a temperature output every 3
seconds); maybe there are some timing issues involved with that? Any
other ideas? This is a student project and I'm hoping to, uh, finish it
on time. Thanks!
Message Edited by hyenah on 05-19-2007 01:59 PM
