• SDI-12 Level Transducer

SDI-12 Level Transducer


  • Custom Level Ranges up to 230 ft (70 m) H2O
  • Unsurpassed Accuracy of ±0.05% Total Error Band
  • SDI-12 Communication Interface
  • Welded 316 SS or Titanium Construction
  • On-board Surge Protection
  • Optional Lifetime Lightning Protection
  • Custom Cable Lengths



  • Well Monitoring
  • Ground Water Monitoring
  • Dewatering
  • Down Hole
  • Surface Water Monitoring
  • Reservoirs
  • Level Monitoring
  • Oceanographic Research
  • Tank Level

The Series 500 submersible hydrostatic level transducer represents the leading edge of level sensing technology available today. Incorporating a highly stable media-isolated sensor, the Series 500 features SDI-12 serial-digital interface. SDI-12 is a standard for interfacing data recorders with microprocessor-based sensors, especially in the environmental monitoring field. The transducer meets the demanding requirements of the USGS Office of Surface Water (OSW) accuracy specification for stage monitoring. The Series 500 is intended for applications with requirements that include battery-powered operation with minimal current drain, low system cost, and use of a single recorder with multiple sensors “daisy-chained” on one cable. It will accommodate cable lengths between sensors and recorder up to 200 feet.

Able to operate from unregulated 12VDC power, each unit contains a microprocessor and EEPROM, which in addition to supporting the SDI-12 interface, are used to implement sophisticated compensation algorithms. This technique, combined with superior media-isolated sensing technology and proven packaging, results in a price/performance combination unmatched by any previous technique. The attached electrical cable is custom manufactured to Pressure Systems’ specifications and includes Kevlar® members to prevent errors due to cable elongation, and a unique water block feature that self-seals in the event of accidental cuts to the cable. Each transducer is shipped with our latest SuperDry™ Vent Filter that prevents moisture from entering the vent tube for at least one year without maintenance, even in the most humid environments.

The Series 500 is CE compliant to EN 61000-6-4:2001 and EN 61000-6-2:2001 and have an IP 68 and NEMA 6P housing protection rating. All KPSI Transducer calibrations are traceable to the National Institute of Standards and Technology (NIST).



Uniquely-Designed Submersible Cable

The attached cable can incorporate either polyurethane or ETFE jacket material. The ETFE (Tefzel® or equivalent) cable jacket provides superior chemical resistance and durability over polyurethane. While more expensive and less flexible then polyurethane, ETFE cable can reduce overall maintenance costs when used in applications involving caustic media, high abrasion, or potential cross-contamination. ETFE is a fluoropolymer recommended over Teflon® for such applications due to its superior tensile strength and flexibility while rivaling Teflon’s chemical resistance.

Both cable types incorporate Kevlar® strength members to prevent errors due to cable elongation, and a unique liner to prevent water intrusion in the event the cable jacket suffers minor cuts. Cable length is determined from the cable end of the transducer and any length of 5 feet or more may be ordered. Polyurethane cable is attached using a polyurethane molded seal while ETFE cable is attached using a compressed Viton® gland seal.

Moisture Protection

Our submersible transducers are equipped with custom, vented cable. The vent provides an atmospheric reference for the sensor, which is necessary for ensuring the highest possible accuracy when making a level measurement. It must be noted that if left unprotected, it provides a pathway for water vapor to enter the level transducer. This vapor will condense into water and could create an offset in the transducer output, or cause permanent damage. For these reasons, a Series 810 desiccant-filled vent filter is provided free of charge with each Series 500 we ship. Our latest SuperDry™ Vent Filter prevents moisture from entering the vent tube for at least one year without maintenance. Replacement filters are available from the factory.

Order information