APT4000 pH/ORP Analyzer

The Honeywell Analytical Process Analyzer (APT) 4000 Series offers the widest available selection of advanced features in a reliable and economical instrument. The advanced features of the APT4000 analyzer guarantee complete reliability. The APT4000 continuously monitors sensor and analyzer electronics and immediately displays diagnostic information at the onset of a problem. If an error is found, the analyzer will indicate the appropriate error code or pictograph, blink a red LED and adjust the error current to 22 mA if desired. A manual loop-back check is available to test the integrity of the 4-20 mA output.

APT4000 has a large front display for quick recognition of process parameters and diagnostics even at a distance. Only the APT4000 employs visual feedback to quicken setup and maintenance times and to minimize errors made during calibrations. Visual feedback refers to pictograph type characters that appear on the display both to prompt and respond to operator and process changes. Pictograph type characters also appear during problem conditions to report diagnostics for easy troubleshooting. The Sensoface pictograph provides constant feedback to the operator on whether or not there is a problem with the cell. These easily learned and recognized symbols make the APT4000 an easy-to-use instrument in any language.

The APT4000 pH/ORP analyzer continuously measures pH or ORP in industrial processes including chemical, pharmaceutical, petrochemical, pulp and paper, and wastewater. The APT4000's NEMA 4X/IP65-rated enclosure is specifically designed to meet the measurement needs of Class I, Div. 2 (non-incendive) and general purpose areas. The analyzer can be used with Honeywell pH or ORP sensors, or a wide variety of compatible electrodes. The analyzer has a universal (20-253 V ac/dc, 45-65 Hz) power supply with one 4-20 mA output, two high/low alarm relays, and an extra relay which can be designated for diagnostic or wash capabilities. Area certification for the APT4000 is FM Class I, Div. 2, Groups A-D (non-incendive). Each analyzer comes standard with CE.

The inputs to the APT4000 pH/ORP include the Honeywell Durafet II non-glass pH electrode (with the Honeywell cap adapter cable), Meredian II glass pH electrodes or Meredian I metallic ORP electrodes. In addition, a wide variety of other compatible pH and ORP electrodes can be used with the APT4000.



  • Large display with easy-to-read 0.75 inch measured value digits
  • Simple operator interface with basic pictographs
  • Application in Class I, Div. 2 or general purpose areas
  • Continuous diagnostics for monitoring calibration, cell health and analyzer self-test
  • Manual loop-back check for integrity of 4-20 mA output
  • NEMA 4X, IP65 plastic enclosure
  • Remote "hold last measured value" capability
  • Second parameter set programmable for alternative applications
  • Wall, pipe or panel mounting
  • Easy installation with preassembled empty enclosure and plug-in terminals
  • Optical alarm with relay contact
  • Dedicated high/low alarm relay
  • Two current outputs available with the second one assigned to temperature
  • Sensocheck monitors condition of the pH/ORP electrodes




APT4000 pH Datasheet