SDI-12 Submersible Depth Sensor | Level & Temperature | Pa993D

SDI-12 Output, Fully Submersible, Very Compact Ø23mm and Surge Protected


The Pa993D SDI-12 submersible depth sensor is an intelligent microprocessor enhanced depth sensor designed for both level and temperature readings as standard.   With its narrow diameter of just 23mm, it is ideal for V-notch weir flow measurement in open channel flow applications and environmental monitoring.

Thanks to its embedded 16-bit microprocessor-based electronics, the Pa993D SDI-12 submersible depth sensor can perform complex linearisation, temperature compensation and calibration to deliver extremely high accuracy of less than ±0.15% full scale, with an option to increase this to 0.1% or 0.06% if required, making them ideal for laboratory & research testing applications, environmental monitoring and flood defence systems.

The Pa993 is perfect for applications using battery or solar panels as it has a very low power consumption and can be powered from as low as 6V supply.  Plus, it is extremely useful in multi-sensor setups as one or more SDI-12 submersible depth sensors can be used to interface with one datalogger.

They have a robust 316 stainless steel silicon sensing element coupled with a choice of Nitrile (NBR) or Viton (FKM), guaranteeing long term immersion protection to 100 metres.  In addition, their moulded cable exit fitted with vented polyurethane (PUR) cable and strain wire provide a high integrity waterproof assembly as standard, making them ideal for the measurement of pressure within rivers, reservoirs and boreholes.

The Pa993D SDI-12 submersible depth sensor has a surge protection circuit to mitigate the effects of electrical transients caused by nearby lightning strikes and power supply fluctuations.

If you need to connect this sensor to a PC, try our USB-SDI12 converter. Using the free downloadable logging software, you can data log up to 10 SDI-12 sensors connected to the USB-SDI12 converter to a PC/Laptop.


  • Ranges:0-1mWG up to 0-100mWG
  • 23mm Diameter
  • Outputs: SDI-12 v1.4 (RS485 Modbus Optional)
  • Environmental Protection: IP68 to 100 metres
  • Accuracy: <±0.15%/FS (Optional 0.1% and 0.06% Versions)
  • Low Power Consumption: <4mA
  • Compact Only 23mm Diameter
  • Accurate Level & Temperature Readings
  • Fully Submersible & Long-Term Immersion Protected to 100m
  • Intelligent 16-Bit Electronics for Complex Calibrations
  • High Integrity Waterproof Assembly
  • Robust Stainless Steel Silicon Sensing Element
  • Protected Against Power Surges from Lightning Strikes


Pressure Ranges: 1, 2.5, 3.5, 5, 10, 20, 25, 50, 75, 100 metres Water Gauge (mWG) *
Pressure Reference: Gauge (Sealed Gauge + Absolute optional)
Safe Overpressure: 150 % Pressure Range
Burst Pressure: 300 % Pressure Range
Supply Voltage: 6-36 Volts DC
Current Consumption: <0.25 (idle), <4 (when active) mA
Digital Output: SDI-12 v1.4 RS485 Modbus
Electrical Connections: Screened polyurethane (PUR) cable with vent tube, strain and drain wire
Level Accuracy: <0.15 (0.1% or 0.06% optional) ±%Pressure Range
Temperature Accuracy 0.5 ±%/FS
Temperature Resolution 0.01 ˚C
Temperature Range Operating: -10 to +60 (non-freezing media only) ˚C
Temperature Range Compensated: 20 ± 20 ˚C
Temperature Effect on Output: <0.01 typical ±%/˚C
Temperature Effect On Zero: <0.01 typical ±%/Rated Output/˚C
Long Term Stability: <0.1 ±%/FS
Environmental Protection: IP68 to 100mWG (10bar)
Weight: 300 (sensor), 48g/metre (cable) grams
Construction / Wetted Parts: 316 St/Steel, Viton (EPDM + NBR optional) + PUR
Permissible Media: All fluids compatible with wetted parts.
Electrical Protection: EMC Immunity: EN50082-1 & Surge (Lightning) Protection: EN61000-4-5
Reverse Polarity Protection: No damage but no function.
*Other engineering units selectable in software: mm, inches, feet, mbar.

Product Dimensions

Pa993D SDI Outline

Wiring Details

Wire Designation
Red +ve supply
Blue -ve supply
Yellow SDI-12 output


Pa993DA-10mWG-AAAV-01-000 (example code) Pa993D A 10mWG A A A V 01 000
Product Family
Pa993D Pa993D
Electrical Output
A = SDI-12 v.1.4 A
B = RS485 Modbus B
Pressure Range
10mWG = 0 to 10 metres of water gauge (H2O) 10mWG
10mWA = 0 to 10 metres of water absolute (H2O) 10mWA
10mWSG = 0 to 10 metres of water sealed gauge (H2O) 10mWSG
Accuracy (Non-Linearity & Hysteresis)
A = <±0.15%/FS A
B = <±0.1%/FS B
C = <±0.06%/FS C
Process Connection
A = Nose Cone (G1/4” DIN 3852 male when removed) A
Housing Material
A = 316 Stainless Steel A
O-Ring Material
V = Viton (FKM) V
N = Nitrile (NBR) N
Cable Length (in metres)
01 = 1 metre 01
10 = 10 metres 10
Specials Code
000 = No Special Requirements 000


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