Isuue with Counter 3 and 4 on PCI-6601

[plindol3]

Hi All,
   I am using counters 1-4 on the PCI 6601 card with NI-DAQmx 8.0 to generate continuous pulses in Labview  8.0. After I configure the counters, I can see the pulses going out on a scope. If I then configure other DIO lines as digital outputs, the pulses on counter 3 and 4 goes away. Counter 1 and 2 is  still okay. Has anyone seen this before. Somehow the configuration on counter 3 and 4 is changing when I try to configure other DIO lines as outputs? For configuration of continuous pulses I  am using the Pulse Train Gen.vi  from the DAQmx PWM Examples.zip folder from NI website minus the while loop and the DAQmx clear Task.vi. The Pulse Train Gen.vi include DAQmx Create Channel(CO-Pulse Generation Frequency).vi, DAQmx Timing(Implicit).vi, DAQmx Start Task.vi, and  DAQmx Is Task Done.vi. For digital outputs I am using DaQmx Write(Digital Bool 1 Line 1 Point). Any suggestions as to why counter 3 and 4 configuration changes and not counter 1 and 2. I need to have these counter going before I configure output lines.   

[Jeff T.]

plindol3,




 There are
some possibilities but it is hard to know for sure until we get a little more
information about your setup.  Could you
please tell us which digital output lines you are using? The PFI lines for
Counter 0 and 1 are reserved exclusively for counter operations but the PFI
lines for counters 2 - 7 are shared with DIO lines.  Could you also post your code so we can see how you are setting up your DAQmx tasks? 
Thanks in advance for your reply.




 Best
Regards,




Jeff Tipps
Applications Engineer
National Instruments

[plindol3]

Hi Jeff,
   I have attached a modified version of my code that demonstrate my problem. It is a simple sequence that  1) sets up counters 1-4, then configure my Digital output lines. The whiIe loop that follows does nothing but let the program runs continuously. If I  configure any of the Digital output lines after my counters are set up, the configuration on counter 3 and 4 gets blown away. It appears there is something going on internal to the DaQmx Write(Digital Bool 1 Line 1 Point).vi. To setup my Digital output lines I used measurement and automation explorer tool. I exported the configuration file and included it in the zip folder as well.
 
 
Patrick


labview8_pulse.zip:
http://forums.ni.com/attachments/ni/70/5451/1/labview8_pulse.zip