Error 56 When Using VeriStand FPGA Addon

Updated Nov 28, 2025

Reported In

Software

  • VeriStand Custom Devices
  • VeriStand
  • LabVIEW

Issue Details

I am using the FPGA Addon Custom Device for my application in Veristand, but when I try to deploy my project I get the following error:

Error 56 occurred at Project Window.lvlib:Project Window.vi >> Project Window.lvlib:Command Loop.vi >> NI_VS Workspace ExecutionAPI.lvlib:NI VeriStand - Connect to System.vi
Possible reason(s):
LabVIEW:(Hex 0x38)The network operation exceeded the user-specified or system time limit.

How can I solve this issue?

Solution

In the FPGA Addon Quick Start Guide.md, it is stated that the FPGA code requires an IRQ (address of 30) to control when the FPGA bitfile starts. This IRQ needs to control when DMA read and write operations begin. If no interrupt is added, you will get timeout error 56.

Here is an example on how to configure this:

Getting Started

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