500 PRO pH/ORP analog sensor

High performance industrial sensor for harsh applications

The 500 PRO series provides the ultimate combination of performance, functionality and durability delivering a competitive offering for harsher industrial applications.



Featuring a triple-junction design with ion traps, reference shielding and Viton® Extreme O-ring protection, the 500 PRO provides enhanced poisoning resistance and chemical protection, extending operational lifetime without compromising performance.

The 500 PRO sensor provides:

Increased efficiency

  • Propriety high performance glassware formulations provide the highest level of reliability and responsiveness
  • Close-coupled temperature measurement ensures high accuracy even with rapid temperature changes

Dependable performance

  • Triple junction design with ion-trap and reference shielding provides enhanced poisoning resistance
  • Unique tertiary cellular junction matrix slows poisoning effects, maximizing sensor lifetime
  • ATEX/IECEx certified for use in hazardous areas
  • Robust PVDF ¾ inch NPT body provides superior mechanical and chemical resistance
  • Each electrode is manufactured to the highest quality standards and provided with a calibration certificate

Modular design

  • Universal ¾ inch NPT design for simplified mounting
  • Available in a range of detached or integral cabling options


Measurement range
pH 0 to 14 pH
Redox (ORP)  –2000 to 2000 mV
Process temperature 
–5 to 105 °C (23 to 221 °F)

Pressure range
0 to 10 bar (145 psi) @ 25 °C (77 °F)

Recommended minimum sample conductivity

50 μS/cm

pH glass
High performance (S) glass (bullet)
High performance (S) glass (flat)
Low temperature (LT) glass (bullet)
High temperature (HT) glass (bullet)
Hydrofluoric acid-resistant (HF) glass (bullet)

Redox (ORP)

Reference system

Ag/AgCl with triple junction, KCl gel electrolyte plus ion trap

Reference junction
Porous PTFE and Viton® Extreme O-rings

Connection type
BNC + Molex

Process connections
¾ inch NPT

Approvals, certification and safety

    Certificate numbers: IECEx BAS 18.0047X

    Entity parameters: Ui = 15.0 V
                                           Ii = 20 mA
                                         Ci = 5 NF
                                          Li = 30 uH
  • CE Mark
    Covers EMC+LV directives (including latest version of EN61010)
  • Regulation 31
    Drinking water approval: Complies to DWI Regulation 31(4)(b)
    Additional tests: BS6920 parts 2.2 and 2.4 on all wetted parts
  • EMC
    Meets requirements of IEC61326 for an industrial environment
  • CRN Approval
    Maximum allowable working pressure (MAWP): 5.58 bar (81 psi)
    Design temperature: -5 ⁰C to + 105 ⁰C (+23 ⁰F to +221 ⁰F)
    CRN number 0F22557 Certificate no. Sira MC220375/00
    Certificate no. Sira MC220375/00


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