Can I use Sealevel reed relay cards to switch other relays or inductive loads?

Sealevel Digital I/O products with reed relays are not designed to switch inductive loads such as the coil on another relay. If you need to switch an inductive load, Sealevel recommends using a Digital I/O product with Form C relays or open collectors outputs. You should remember to place a diode parallel to the coil or the inductive load to suppress the inductive kickback voltage. Failing to install a diode will shorten the life of the relay contacts or open collector outputs. In the specific cases of the SeaI/O 530 and 540 Digital I/O products, the protective diode is integrated into each open collector output, which often makes these products a good choice for switching current to inductive loads.