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Simultaneous I/O : real-time writing aquired and processed data
epr
Member
07-11-2002 09:03 AM
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Bonjour,
I am realizing a servo-control system (real-time) that needs:
-continuous buffered aquisition of data
-immediate processing on about 512 samples
-continuous generation of processed data
The delay between Input and Output isn't my problem yet.
Therefore I configure ouside a while loop both AI and AO (same device, 1 channel for Input, 1 channel for Output) with AI/AO CONFIG, then I do AI START and blank AO WRITE followed by a AO START (scan rate 20000 samples/s for both I and O).
Inside the while loop (that stops on demand or on error), I do an AI READ of 512 samples, that are processed (derivated) and directly writen with AO READ.
There is no wiring problem and as I start running, an error
message immediately appears :
ERROR -10026 on AO Control : The number of buffers or the buffer size is not allowed...
Buffer size is fixed to 40000 for both input and output.
I notice that continuous aquisition, processing and displaying works well for those values (scan rate, number of scans to read and buffer size). It should be a configuration problem of the output.
My hardware: PCI-6110E board, BNC-2110 device, and Pentium III processor.
I just want to know how to configure this simultaneous I/O on shared data ; the actual possibility of doing such an effective real-time servo-control will be a further problem.
Does PCI-6110 board have separate buffers for I an O ? I don't think so since the DAQ manual speaks about "circular buffer" (FIFO). May I have to explicitely precise I want to share a buffer for I and O ?
Thanks,
JL from Laboratoire Kastler-Brossel, France
I am realizing a servo-control system (real-time) that needs:
-continuous buffered aquisition of data
-immediate processing on about 512 samples
-continuous generation of processed data
The delay between Input and Output isn't my problem yet.
Therefore I configure ouside a while loop both AI and AO (same device, 1 channel for Input, 1 channel for Output) with AI/AO CONFIG, then I do AI START and blank AO WRITE followed by a AO START (scan rate 20000 samples/s for both I and O).
Inside the while loop (that stops on demand or on error), I do an AI READ of 512 samples, that are processed (derivated) and directly writen with AO READ.
There is no wiring problem and as I start running, an error
message immediately appears :
ERROR -10026 on AO Control : The number of buffers or the buffer size is not allowed...
Buffer size is fixed to 40000 for both input and output.
I notice that continuous aquisition, processing and displaying works well for those values (scan rate, number of scans to read and buffer size). It should be a configuration problem of the output.
My hardware: PCI-6110E board, BNC-2110 device, and Pentium III processor.
I just want to know how to configure this simultaneous I/O on shared data ; the actual possibility of doing such an effective real-time servo-control will be a further problem.
Does PCI-6110 board have separate buffers for I an O ? I don't think so since the DAQ manual speaks about "circular buffer" (FIFO). May I have to explicitely precise I want to share a buffer for I and O ?
Thanks,
JL from Laboratoire Kastler-Brossel, France
Gerald Albertini
NI Employee (retired)
07-11-2002 09:59 AM
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Monsieur,
I attach a VI that shows how to perform the task you're trying to achieve.
Additional examples are available in LabVIEW, for instance, the VI called "Simul AIAO Buffer(E-series).vi" available in "Help>>Examples>>I/O interfaces>>Data Acquisition (DAQ)>>Simultaneous Analog I/O.
I hope this will help !
N'hesitez pas a me contacter directement si vous avez besoin de plus d'informations.
Mon adresse email est : gerald.albertini@ni.com
Best regards
I attach a VI that shows how to perform the task you're trying to achieve.
Additional examples are available in LabVIEW, for instance, the VI called "Simul AIAO Buffer(E-series).vi" available in "Help>>Examples>>I/O interfaces>>Data Acquisition (DAQ)>>Simultaneous Analog I/O.
I hope this will help !
N'hesitez pas a me contacter directement si vous avez besoin de plus d'informations.
Mon adresse email est : gerald.albertini@ni.com
Best regards
