DDK DAQ Qnx

[eesen]

Hi,

I try to use DDK for DAQ 6143 under Qnx. In the shipping example, there are on demand and finite sample acqusition examples. I want to do continuous acqusition. In the example, implementation of the aistart has been done but not aistop. Can the implementation of the aistop be as following?

aistop {

theSTC->AI_command_2.writeAI_STOP_Pulse(1);

theSTC->AI_command_2.writeAI_Start1_Pulse(0);

}

[Tom_W_[DE]]

Hi eesen-

In the case of On Demand or Finite acquisitions the AI timing engine will disarm automatically; there is no need to do it explicitly.  That said, the aiReset() function from the ni612x_3x DDK examples would also work to disarm and reset the AI timing engine for the 6143.

Thanks-

[sternj]

Hi Tom,

    What about for the 6034E card?  I also want to achieve continuous sampling.  I am having trouble manipulating the theSTC->AI_SC_Load_A.get/read/writeRegister() and theSTC->AI_START_STOP_Select.setAI_STOP_Select() features.

Thanks.

[Tom_W_[DE]]

Hi sternj-

In order to configure the device for continuous operation, you'll need to set the AI_Continuous bit from the AI_Mode_1 register in the STC.  With this setting any SC_TC events (i.e. the event that stops the acqusition in a finite configuration) will be ignored, and the NumberOfScans setting is largely irrelevant.

There's more info in the STC Technical Reference manual, namely on pages 62 and 78, though the entire AITM section is a good read.  You might also consider referring to the M Series examples for the MHDDK.  From M Series ai.cpp, the function aiNumberOfSamples() might be of use as an example of the continuous mode setting.  M Series aiex3.cpp shows that function in the context of a hardware-timed AI operation.

Thanks-

[sternj]

Thanks, Tom. I simply decided to not arm the SC counter (by calling the AI_Command_1.setAI_SC_Arm(0)). I could not find the appropriate Continuous option using the supplied tSTC.h file.

Joe