The Walchem WDP420-542N controller is now obsolete and has been replaced by the WDP420-542U controller which now has integrated USB datalogging and software upgrade capability. Otherwise, both the WDP420-542N and the WDP420-542U have the same specifications with w/ 2 pulse proportional and 2 on/off control outputs and diagnostic alarm relay, hardwired, cable glands, single isolated analog (4-20 mA) output, two submersion flat ph electrodes without auto temp c.
Please click here to view and/or purchase the new replacement controller and to view literature.