Good morning Mark,
Thanks for contacting National Instruments with your issue, we'll try our best to resolve it for you as quickly and efficiently as possible.
The minimum trigger hold-off time for the NI PXI/PCI-5124 is 2 us with TDC disabled and 10 us with TDC enabled.
You can take a look at any other trigger specifications for the NI PXI/PCI-5124 below:
https://www.ni.com/docs/en-US/bundle/pxi-pci-5412-specs/resource/371468e.pdf
Best of luck with your project.
Sincerely,
Minh Tran
Applications Engineering
National Instruments
