National Instruments AT E Series User Manual
Page 160
Appendix C
Common Questions
C-8
ni.com
The counter/timer examples supplied with NI-DAQ are not compatible
with an AT E Series device. Where can I find examples to illustrate the
use of the DAQ-STC as a general-purpose counter/timer?
If you are using the NI-DAQ language interface and a C compiler under
DOS, a new subdirectory called
GPCTR
, which lies beneath the
examples
directory, contains 16 examples of the most common uses of the
DAQ-STC.
Do the counter/timer applications that I wrote previously work with
the DAQ-STC?
If you are using NI-DAQ with LabVIEW, some of your applications drawn
using the CTR VIs do still run. However, there are many differences in the
counters between the AT E Series and other devices; the counter numbers
are different, timebase selections are different, the DAQ-STC counters are
24-bit counters (unlike the 16-bit counters on devices without the
DAQ-STC).
If you are using NI-DAQ or Measurement Studio, the answer is no. The
counter/time applications that you wrote previously do not work with the
DAQ-STC. You must use the GPCTR functions; ICTR and CTR functions
do not work with the DAQ-STC. The GPCTR functions have the same
capabilities as the ICTR and CTR functions, plus more, but you must
rewrite the application with the GPCTR function calls.
I’m using one of the general-purpose counter/timers on my
AT E Series device, but I do not see the counter/timer output on
the I/O connector. What am I doing wrong?
If you are using NI-DAQ or Measurement Studio, you must configure
the output line to output the signal to the I/O connector. Use the
Select_Signal
call in NI-DAQ to configure the output line. By default,
all timing I/O lines except EXTSTROBE* are high-impedance.
How does NI-DAQ treat bogus missed data transfer errors that can
arise during DMA-driven GPCTR buffered-input operations?
When doing buffered transfers using GPCTR function calls with DMA,
you can call
GPCTR_Watch
to indicate dataTransfer errors. NI-DAQ takes
a snapshot of transfers and counts how many points have been transferred.
If all the points have been transferred and the first instance of this error
occurs, NI-DAQ returns a gpctrDataTransferWarning indicating that the
error could be bogus. If all the points have not been transferred, NI-DAQ
returns the genuine error. The error continues to be returned until the