Chapter2 Usingthe SCXI-119X
SCXI-1190/1191/1192User Manual 2-4 ni.com
SCXI backplane. National Instruments is not liable for any damages or injuries resulting
fromexceeding maximum voltage ratings. Refer to Appendix A, Specifications,for
specificinformation.
Caution Alwaysdisconnect all signals from the front connectors a nd poweroff the SCXI
chassisbefore removing the SCXI-119Xfrom the chassis. Observe electrostatic discharge
handlingprecautions during and after removal of the module, or when connecting and
disconnecting signals on the front panel.
Contact Protection
Caution Thecontacts of the relays are rated for a life of 5 × 106mechanical operations
when operated with no signal or a very small signal present. When high-powerlo ads are
switched,arcing can occur across therelay contactsthat will reduce their useful life. See
Appendix A, Specifications, for lifetime ratings for each module. If your setup allows, it is
alwaysbest to turn off the input signals connected to the switch mo dule during the
switching operation to avoidcontact arcin gw ithin the switch. Switching large inductive
loadscan also cause contact arcing. In such instances, install a flyback diode or varistor
across the inductance to protect the switch.