Deploying NI Veristand Models to a Real Time Target

[nyawako]

Hi All,

 

I desperately need some help with some application i’m working on. I’m trying to read some accelerometer measurements into NI Veristand but coming up with an error all the time during the deployment stage to the real target which i have atttached. I can’t quite figure out what to do about it. I’m using a real-time device with a PXI-4461 module. I have checked that i can read all sensor measurements in MAX as attached. The error message is as follows:

 

Initializing deployment...

Waiting for the target to report its state...

Initiating FTP connection...

System Definition File -> Acquisition.in4

Restarting system...

Restarting target into run mode...

The target encountered an error and reset. Verify that the system definition file and the target resources are valid. You must deploy a new system definition file or reboot the controller to correct this problem.

 

Error -200757 occurred at DAQmx Start Task.vi:1

 

Possible reason(s):

Measurements: Sample Timing Type is set to On Demand which is not supported for analog input on this device.

Set Sample Timing Type to Sample Clock. You can achieve this whlie setting related properties through DAQmx VIs or functions for configuring timing.

Task Name: Dev6_AI

[david.bolt]

Dear nyawako

The error you are receiving is a resultant of somewhere in your code using the DAQmx Vi's, you have selected 'On-Demand' sampling. On-demand sampling is not supported on the 4461. The reason the property: DAQmx_SampTimingType returns On-demand, is because with our DAQ driver, when no sampling timing type is default set to on-demand. When programming the 4461, a sampling clock is always required.

In terms of your application, set a sampling clock to a sampling that isn't 'On Demand' (eg, continous, or finite) and this will resolve the errors your are throwing.I have attached a screenshot of the acquisiton modes that can only be selected for this card.

Message Edited by david.bolt on 05-25-2010 09:00 AM

[nyawako]

Hi David, sorry i have been away most of last week. I'm still ending up with the same error message and can't quite figure out how to change the timing settings.

Now, i have a quick question, must i use Custom Devices for this?

Many thanks,

Donald

[StephenB]

Hi Nyawako,

I'm not sure if David realized you're using NI VeriStand. In this case you cannot change the DAQmx code, it is built into NI VeriStand.  Unfortunatley your 4461 doesn't support Hardware Timed Single Point, which is mentioned in the NI VeriStand help as strongly reccomended for DAQ hardware to be supported.

The easy work around to not supporting HWTSP is to turn it off (the checkbox to turn off HWTSP on the DAQ page) and then you use one sample on demand instead. This method is much lower performance, but it may work. Unfortunatley the 4461 doesn't support that either. DSA based cards require a minimum sample rate that can't be done with one sample on demand.

You're only course here is to create a custom device: http://zone.ni.com/devzone/cda/tut/p/id/9348

Depending on your requirements, you might set the device to a certain sample rate and then average the samples and return one value to the system.

Take care,

[Arnold91]

Hi,

Sorry for upping up this old post but I am like Nyawako, I use a PXI-4461 card and I wanted to devellop a PID application in order to control my vibration system fed back with an accelerometer acquisition. As mentionned in Labview general help, control loop can only be achieve with "hardware timed single point" argument on DAQmx timing sample clock vi.

Unfortunately, as Stephen B mentioned it, PXI-4461 is not "hardware timed single point" capable. It's the only post I found over the web where it is mentionned !!! 

So where in NI specs they do mention explicitely which DAC/CAD cards accept "hardware timed single point" argument ???? and why most NI commercials don't know that ?!

I am very surprised that a 3k$ PXI card specifically designed for sound and vibration isn't RealTime PID capable !!!

Best Regards.