The Walchem WDB400-5NNN controller is now obsolete and has been replaced by the WDB400-5NNU controller which now has integrated USB datalogging and software upgrade capability. Otherwise, both the WDB400-5NNN and the WDB400-5NNU have the same specifications with hardwired, cable glands, no 4-20 mA output, no electrodes, integrated datalogging and config file import/export via USB flash stick.
Please click here to view and/or purchase the new replacement controller and to view literature.