Error -200077 When Deploying in VeriStand™

Issue Details

I am unable to deploy thermocouple channels in VeriStand. When I try to deploy, I receive a NumOfWarmupIters error, along with a message indicating that the requested sample rate is too high and unsupported:

Error -200077 occurred at ProjectWindow.lvlib:Project Window.vi > > Project Window.lvlib:Command Loop.vi > > Project Window.lvlib:Connect to System.vi Possible reason(s): Requested value is not supported value for this property. The property value may be invalid because it conflicts with another property.

Solution

To resolve this issue, adjust the Acquisition Settings in VeriStand and verify the device configuration:

1. Enable Slow Background Conversion Mode
2. Set Sample rate to -1
   • This sets the acquisition timeout to infinite and prevents timeout errors during device startup
3. Verify that the following conditions are met to allow Slow Background Conversion Mode:
   • Ensure the Sample Mode is not set to Waveform.
   • Ensure hardware-timed single-point sampling is enabled for the AI channels in the DAQ Device configuration.
   • Ensure the device is not configured as the chassis master hardware synchronization device.
4. Verify the DAQ device order in the system definition:
   • Ensure that the SC Express device (for example, PXIe-4353) is not listed as the first DAQ device.
   • If it is listed first, remove the device and re-add it so it is no longer the first DAQ device.

Refer to How to Set Slow Acquisition Rate for NI-DAQmx SC Express Devices in VeriStand for additional configuration details.

Additional Information

SC Express devices use delta-sigma analog-to-digital converters (ADC). These ADCs apply digital filtering and require a number of samples to be acquired before valid data can be returned. As a result, there is an inherent warmup period before the first samples are available.

In VeriStand, the loop rate and acquisition timing can be too short to accommodate this warmup period, which can result in deployment failures or errors. Setting the sample rate to -1 allows the driver to wait indefinitely for data, avoiding timeout during this warmup phase. The actual sampling rate is then determined by the configured conversion mode on the device.

Although a fixed sample rate can be configured, errors may still occur if the warmup time exceeds the timing constraints. For this reason, it is recommended to use the maximum conversion rate together with Slow Background Conversion Mode enabled when working with SC Express devices.