ER-8/16 User Manual and Specifications This manual describes the electrical and mechanical aspects of the ER-8 and ER-16 and contains information concerning their setup, operation, and safety. Both the ER-8 and ER-16 are single-pole double-throw (SPDT) relay accessories for use with other data acquisition (DAQ) products. The ER-8 has Edition Date: December-1996 URL: http://digital.ni.com/manuals.nsf/websearch/0CC0C559A9660A9D8625665E00635884