2 channel sine wave generation and 2 channel dc voltage generation are not working with pci-6723

[embedded systems engineer]

Hi
i have developed one programme which generates 2 channel sine wave and 2 channel dc voltage and 8 digital lines using pci-6723 , but now when trying to run the programme iam able to generate only sine waves dc voltages cannot be changed in the run time ,kindly look into my programme since its very urgent
actually i have used 3 vis in one programme hence there might be syncronization , Mr SPENCER has sent the 2 channel sine wave.

[DOC-doc]

Hi

I don't think you can have 2 different threads accessing for the same functionnality in the card.
(At least it was the case with DAQ) : you can input AO, output AO, output DIO all this at the same time, but you cannot tell the card to do 2 different things, with the same processor, at the same time (imagine there is a processor for AI, one for AO and one for DIO).

I therefore would link together the 2 sine waves and the AO array (must have the same dT than the sine waves) and write this alltogether into the DAQMX write (the top one)

Doc-Doc

[Dr._Imad]

You should be able to generate both the sine waves and the DC outputs.
The analog output vi's (for the DC case, channels 2,3)has to be in a while loop too in order to be able to update them during run time.

[DOC-doc]

Can you really have two signal generations at two different pace on the same AO board ?

Doc-Doc

[Dr._Imad]

Yes, you can generate buffered outpout and dc output on the same card at the same time.
The cards that I used in these applications are
AT-AO-6/10
PCI-6713

The PCI 6723 is no different.
I will be using also a PCI 6722 to do the same thing.
(I will be using NIDAQ 7.3 (7.2 had a bug in it and rendered the card unusable)

[DOC-doc]

do you mean that it is the number of DMA which is important ?

Could you also generate to buffered acquisition on the same AO (say channels 0..4 for one buffer and 5..7 for the other under different timing conditions) ?

Can the DC value be updated anytime or at the end of a buffer ?

[Dr._Imad]

These cards use a combination of IRQ and DMA depending on the availabilty (it is done behind the scene). Obviuosly, for buffered output DMA is used.

"Can the DC value be updated anytime or at the end of a buffer ?"
These are updated the moment the values are outputed. In my work I never noticed any delay.

"Could you also generate to buffered acquisition on the same AO (say channels 0..4 for one buffer and 5..7 for the other under different timing conditions) ?"
You can generate buffered output on more than one channel group (is there a maximum? I do not know).

"under different timing conditions"
If you mean different frequencies ? Yes, but this acheived by placing more than one cycle per buffer for one group (yo
u will have frequency F on one group, and frequency XF on the other group) where X is the number of cycles per buffer. It is the same update clock in the card that is used. (therefore, they are not really independent).
The ATAO -10 card has two indepedent clocks where you can have one set at a particlular frequency with an update rate from clock 1, and the other set from clock 2. (If I remember correctly, channels 0-7 use one clock,8,9 use the other clock). Then you can generate truely two independent signals. Obviously, you cannot use the ATAO with DAQ MX, and because it is an ISA board, you will not have a use for it any more. I used it when ISA was king.
I think NI has released new AO card that has more than one clock ( the PCI 6722 is not the one).

[embedded systems engineer]

Hi
Dr Imad well i have got lot of replies but i wannna go in a simple approach , iam sending my new programme in this programme iam using a knob and a simulate signal
in this case i observed dc value is once updating
since 3 days iam struggling can u plz look into my programme , if u can modify the only dc portion with continuous update iam really very thankful to u
Regards
embedded systems engineer (rajesh)

[Dr._Imad]

see attached vi

[embedded systems engineer]

Hello Dr Imad ,
i have executed your programme ,at first i didnt got the output, but when i removed the start task of analog channel 2, then sine wave started coming.and also i have got the error-200022 the specified source has been already reserved by another task.
i think this is bcos of the we are trying to write to the DAQmx 2 times.
if u have pci-6723 kindly execute and help to proceed
iwant to change the dc analog values in the run time along sine wave generation

THANKS IN ADVANCE
REGARDS
RAJESH