Re: Handling Instrument Error States

See creating user defined error codes in the help for labview.

Imho, checking of instrument errors belongs in the recomended Prefix
Error Query VI (where prefix is the instrument model). You should get
the latest copy of the templates, guidelines, etc. from <A
href="http://www.ni.com/devzone/idnet/development.htm">here</A>. Do
not put any range checking in the driver VIs themselves. The
instrument itself should be able to determine if a value is out of
range and the driver should be calling the error query function. You
limit the driver by using LabVIEW for things likerange checking. As an
example, say you've a power supplu model A with a max current of 5
amps. Someone tries to program it for 6 amps and the instrument should
put a message in it's error queue that is read and the programmer
fixes his program. Now, model B of the same supply is released and it
has a max current of 7 amps. If you had limited the current range in
your driver, the driver would not be useable for the new model supply.

If you follow the guidelines, you'll have a much better chance that
your instrument driver will be accepted by NI if that's your ultimate
goal.

Imho, checking of instrument errors belongs in the recomended Prefix
Error Query VI (where prefix is the instrument model). You should get
the latest copy of the templates, guidelines, etc. from <A
href="http://www.ni.com/devzone/idnet/development.htm">here</A>. Do
not put any range checking in the driver VIs themselves. The
instrument itself should be able to determine if a value is out of
range and the driver should be calling the error query function. You
limit the driver by using LabVIEW for things likerange checking. As an
example, say you've a power supplu model A with a max current of 5
amps. Someone tries to program it for 6 amps and the instrument should
put a message in it's error queue that is read and the programmer
fixes his program. Now, model B of the same supply is released and it
has a max current of 7 amps. If you had limited the current range in
your driver, the driver would not be useable for the new model supply.

If you follow the guidelines, you'll have a much better chance that
your instrument driver will be accepted by NI if that's your ultimate
goal.