The SDM-CD16D is a 16-channel device that expands the digital output capabilities of Campbell Scientific dataloggers. Output voltages are 5 V (nominal, high state) and 0 V (nominal, low state). Output source current is 36 mA at 3 Vdc. The SDM-CD16D is intended for use with dc-powered devices only, to drive normal logic level inputs as well as directly control low voltage valves and relays.

A related Campbell SDM product, the SDM-CD16AC, is rated for ac use.