How Should I Connect an Emergency Stop to an NI-9350/9351 Functional Safety Module

Updated Dec 11, 2023

Environment

Hardware

  • NI-9351
  • NI-9350
  • Emergency Power Switch

I have an NI 9350/9351 functional safety module which I need to connect an emergency stop (E-stop) button to, how should I go about doing this whilst maintaining Safety Integration Level (SIL) standards?

Note: The C Series Functional Safety Modules are no longer sold by NI.

In the NI-9350 getting started guide, a number of different input/output configurations are specified. As most emergency stop (E-stop) buttons are normally closed switches (NC), the "Single Input with Test Pulse Connection" and "Dual Input with Test Pulse Connection" configurations should be used, these are both shown below.

Single Input with Test Pulse Connection

This configuration should be used for an E-stop with one NC connection. 
 

Dual Input with Test Pulse Connection

This configuration should be used with E-stops that have dual NC connections.

 
Note: Use one of the following pairs for dual switches: DI0 and DI1, DI2 and DI3, DI4 and DI5, or DI6 and DI7.