National Instruments NI 9375 Getting Started Manual page 17

I/O Protection
Each DO channel on the NI 9375 has circuitry that protects it
from overcurrents resulting from a short-circuit or faulty loads.
Caution
conditions can damage the NI 9375. Check the voltage
specifications for all devices that you connect to the
NI 9375.
When a short circuit is present on a digital output channel, the
DO channel cycles off and on until the short circuit is removed or
the current returns to an acceptably low level. An overcurrent
state can affect the performance of the NI 9375 and other
modules in the system. To ensure safe and proper operation, the
digital outputs should not exceed the maximum continuous
output current specification.
Overvoltage and reverse bias voltage
NI 9375 Getting Started Guide | © National Instruments | 17