CS Instruments FA 500 - Dew Point Sensor With Integrated Display And Alarm Relay


FA 500 is the ideal dew point sensor with integrated display and alarm relay for refrigeration, membrane and desiccant driers.


CS Instruments

CS Instruments

CS Instruments GmbH & Co. KG with locations in 24955 Harrislee and 78052 Villingen-Schwenningen/ Tannheim, is managed by Dipl. Eng. (FH) Wolfgang Blessing as sole Managing Director.

CS Instruments GmbH was established in the year 2002 by Christian Schuldt and Wolfgang Blessing as equal shareholders/Managing Directors.

Wolfgang Blessing already was sound a specialist on the sector of compressed air technology resp. industrial measurement technology long before the establishment of CS Instruments GmbH in the year 2002. Prior to the foundation of CS Instruments GmbH Dipl. Ing. (FH) Wolfgang Blessing acted for more than 10 years as primarily responsible product manager for industrial measurement technology at a worldwide known manufacturer of measuring instruments for compressed air and gases in the Black Forest. The technical knowledge and experience matched with the long-term practical knowledge was the corner stone for the success of CS Instruments.


  • NEW: Modbus-RTU interface
  • NEW: Higher resolution of sensor signal caused by the improved evaluation electronics
  • NEW: Sensor diagnosis on site with a portable device or CS Service Software
  • Integrated display
  • Threshold value adjustable via keypad alarm relay (max. 60 VDC, 0,5 A)
  • Pressure-tight up to 350 bar (special version)
  • Extreme long-term stability
  • Quick response time
  • 4…20 mA analogue output
  • 2 versions: Refrigeration driers and desiccant driers


  • The integrated display shows the dew point in big figures as well as further humidity parameters on two more display pages. By means of the arrow key it can be browsed between the display pages.
  • The alarm threshold value for the integrated relay can be entered via the keys. Apart from the alarm threshold it is also possible to enter the hysteresis freely.
  • The 4…20 mA analogue output can be scaled freely resp. also allocated to one further parameter, e.g. g/m³.
  • If requested the sensor can also reckon back from the measured pressure dew point to the atmospheric dew point upon entering the system pressure of the compressed air plant and the reference pressure (atmospheric pressure).


  • Measuring range: -80…20 °Ctd, -60…
    30 °Ctd,
    -20…50 °Ctd, or
    0…100% RH
  • Accuracy: ± 1 °C at +50…-20 °Ctd
    ± 2 °C at -20…-50 °Ctd
    ± 3 °C at -50…-80 °Ctd
  • Pressure range: -1…50 bar
    Special version up to
    500 bar
  • Power supply: 24 VDC (10…36 VDC)
  • Protection class: IP 65
  • EMC: In acc. with DIN EN
  • Operating temperature: -20…50 °C
  • Connection: 2 x M12, 5-pin for analogue output, Modbus-RTU
    and alarm output, M-Bus
    Ethernet (PoE) (optional)
  • PC connection: Modbus-RTU interface
    (RS 485)
  • Output: (3-wire) 4…20 mA = -80…20 °Ctd
    4…20 mA = -60…30 °Ctd
    4…20 mA = -20…50 °Ctd
  • Burden for analogue
    < 500 Ω
  • Alarm relay: NC, max. 60 VDC, 0.5 A
  • Screw-in thread: G 1/2″
  • Dimensions housing: 76.5 x 85 x 75 mm (WxHxD)

Additional Informations

  • Accessories :
    • Standard measuring chamber : for compressed air up to 16 bar
    • High-pressure measuring chamber : for compressed air up to 350 bar
    • Control and calibration set for dew point sensors : is screwed onto the dew point sensor and therefore enables an easy and low-priced possibility for on-site control and calibration down to -20°Ctd.
    • Measuring chamber stainless steel 1.4305, for dew point measurement : in gases / air up to 350 bar

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