The Walchem WPH420-121N controller is now obsolete and has been replaced by the WPH420-121U controller which now has integrated USB datalogging and software upgrade capability. Otherwise, both the WPH420-121N and the WPH420-121U have the same specifications with proportional control outputs, 120 VAC, pre-wired with 6” pigtails (wph410) or with 10’ cables (wph420), two isolated analog (4-20 mA) outputs, preamplifier (190783) w/10’ cable, pre-wired.
Please click here to view and/or purchase the new replacement controller and to view literature.