using the SCAN_Start function

[Wali Akthar]

Hi,
I have trying to acquire multiple channels of data using the SCAN_Start function on a PCI-MIO-16XE-10 device using the NI-DAQ driver software.
When I try to execute the call to SCAN_Start using the following parameters device=1, buffer = ai_buffer[4096], count = 4096, sampTimebase = 1, sampInterval = 4883, scanTimebase = 1, scanInterval = 1000
I get a status error -10697 which states Unable to convert your timebase/interval pair to match the actual hardware capabilities of this board. But I have used this function before and worked fine. In this particular function I am trying to playout multiple channels of data and simultaneously aquire them back in where as other functions I just acquiring or playing out. The RATE value
I am using is 204.8.
In this particular function the series of function calls are as follows:

Init_DA_Brds
WFM_Scale
Set_DAQ_Device_Info
WFM_Group_Setup
WFM_Load
Select_Signal
Select_Signal
WFM_Rate
WFM_ClockRate
DAQ_Config
DAQ_Rate
SCAN_Setup
WFM_Group_Control
SCAN_Start
WFM_Check
DAQ_Check
WFM_Group_Control
SCAN_Demux

Any help would be gratefully appreciated!
Thanks in advance.

[afreen]

Hi Wali,

On E-series boards (your PCI-MIO-16XE-10 is an E-series device) you cannot have a value of 1 for the scanTimebase parameter in the SCAN_Start function. I would recommend that you use either -3 (20MHz clock) or 2 (100 kHz clock) and then set your other parameters accordingly.

Also, I would advise you not to use the DAQ_Rate function. This function is a very old one and was supposed to be used when E-Series boards were not around. You can see the following KB (linked below) for more information on this.
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/862567530005f09f862569de005c87ea?OpenDocument

The following example should show you how to output a waveform without using the DAQ_Rate function:

http://zone.ni.com/devzone/expl
prog.nsf/6c163603265406328625682a006ed37d/ac7c06d542e7e9eb8625687c006d1ddf?OpenDocument

Best Regards,

Afreen Siddiqi
National Instruments

[Wali Akthar]

Hi Afreen,

Thanks for your answer.
I've had a look at the example.
I am very new to this kind of stuff so please bear with me.
I can't quite figure out what other function apart from DAQ_Rate I should be using.
I have read the first link but in the online help it states the following
Range: -3: 20 MHz clock used as the timebase (50 ns) (E Series only).

1: 1 µs.
2: 100 kHz clock used as the timebase (200 ns) (E Series only).
2: 10 µs.
3: 100 µs.
4: 1 ms.
5: 10 ms.

Whereas the link states "Currently, it says that -3 and -1 are valid codes for the timebase parameter" which seems to conflict with what the online help says??


Also in the example it uses the high-level function WFM_Op which (from reading the document title NI-DAQ for PC
Version 6.9.1 User Manual) to output a waveform. But I am using DAQ_Rate to input a signal (not output).
For waveform generation I am using WFM_Rate.
In my code what can I substitue the call to DAQ_Rate for?

For the card I have what should the timebase and sampleInterval be if I want to input a signal which has a sample rate of say 204.8??