Scan Engine update rate for 9145 EtherCat Expansion Chassis

[holteeww]

We have a PXIe-8840 RT controller and would like to expand our system to include a 9145 with 4 9224 C Series modules.  If our PCL is running at 1kHz, can we use the Scan Engine Custom Device to stream 32 measurements from the 9145 at 1kHz?  Just wondering if there are any bandwidth limitations with this configuration.

[ATarman · Accepted solution]

I would not expect that you would have a problem.  We have run at 1 kHz and higher with over 20 channels in the 9144 EtherCAT chassis, using the VeriStand Scan Engine for EtherCAT custom device.  

[holteeww]

Thanks for the response.

[Nickede]

We have been using the older NI-9144's with multiple daisy chained racks and modules with the PCL loop at 1Khz no issues

However remember to set the scan rate of the module to the lowest setting

Example:

NI-9239 voltage in card:

scan rates range from 50 kS/s to 1.6313 kS/s

Because the PCL is at 1KHz and the scan rate of the module is at 1.63 kS/s (1.63KHz) the ac content will be aliased so use caution in recording the data as waveform quality