Keller Submersible Level Transmitter

The Keller Acculevel SDI high accuracy level transmitter incorporates microprocessor-controlled signal conditioning to provide outstanding accuracy over temperature. It provides dual digital outputs, one SDI-12 and one RS485. Both allow users to retrieve both level and temperature data and interface with a PC or existing SDI-12 logger and telemetry units.


  • Guaranteed lightning protection
  • Standard ±0.1% FS TEB or optional USGS OSW accuracies available
    – ±0.1% FS TEB on ranges up to 900 ft W.C.
    – Meets OSW spec on ranges up to 70 ft W.C. from 0…40°C
  • 16-bit internal digital error correction for cost-effective low Total Error Band (TEB)2
  • Selectable digital outputs (SDI-12 or RS485) for maximum versatility
  • RS485 modified-MODBUS and SDI-12 V1.3 protocol compatibility
  • 316L stainless construction standard
  • 2-year warranty covers defects in materials and workmanship
  • Built in the U.S.A. ARRA Section 1605 Compliant

The Acculevel SDI provides outstanding Total Error Band (TEB)2 accuracy for reliable, accurate measurements in real-world conditions.

The Acculevel SDI combines SDI-12 and RS485, two industry standard digital communication protocols, making it ideally suited for environmental monitoring applications such as surface water, streams, and reservoirs using existing SDI-12 monitoring equipment.

The Acculevel SDI is ideal for remote applications where battery-powered operation with minimal current draw and networking multiple sensors to a data recorder are required. And, the included lightning protection makes it more robust for installation in areas prone to high current and voltage transients.


Pressure Ranges1Relative: Infinite between 0-3 and 0-900ftWC
Absolute: Available on request
Accuracy2,3,4Pressure: Standard ±0.1% FS TEB
– Optional ±0.01 ft WC when reading ≤ 10ftWC or ±0.1% of reading >10 ftWC
Temperature: typ. ± 0.3 °C
Output5Digital: SDI-12 + RS485
Pressure Resolution: 0.0005% FS
Temp. Resolution: < 0.01 °C
Comm. Protocol: SDI-12 V1.3, MODBUS RTU
Baud Rate: 1200 bits/s
CE: EN50081-1, EN50082-2

1. Level range may be specified in units of bar, mbar, mH2O, psi, ftWC, or inWC.
2. Total Error Band (TEB) includes the combined effects of non-linearity, hysteresis, and non-repeatability as well as thermal dependencies, over the compensated temperature range.
3. Optional accuracy is written in compliance with USGS OSW specification mandates.
4. Optional accuracy is written in compliance with USGS OSW specification mandates and limited to a compensated temperature range of 0…40° C.
5. The Acculevel SDI can communicate in either SDI-12 or RS485 at any one time. By default, the Acculevel SDI will ship in SDI-12 mode. A USB Dongle is required to change to RS485 mode.

© 2018 Forest Technology Systems Ltd.

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