a sealed contact relay for use in industrial control systems includes a solid state digital programmable timer which controls the operation of a timed relay coil . an instantaneous relay coil is also included and each of the coils operates two sealed contact switches which are contained in field replaceable cartridges . a timing light indicates the state of the timed relay coil and it blinks while the digital programmable timer is timing . the timer mode and the duration of the timed interval are selected by placing a uniquely molded insert into a four - pole switch receptacle .