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H1QL Liquid Level Sensor Datasheet


H1QL is an industrial-grade, fully calibrated digital pressure transducer; primarily designed to measure levels of liquids in tanks or level of open water. The solution offers a wide range of electrical connectivity options including RS485 and USB. The unit communicates using multiple protocol options. The unit offers multiple choices of physical connectors and can be used in a variety of environments.


Liquid level sensor H1QL is designed for precision measurement of level of liquids inside tanks or containers or open water. The main measurement body is made from stainless steel, so any measured medium which does not react with stainless steel (DIN 1.4301) can be measured.

The sensor uses very sensitive probe to measure difference in atmospheric pressure and hydrostatic pressure in the tip of the probe. The sensor is fully calibrated and linearized.

Sensors are designed, assembled and tested in EU under full EU legislation.

Mechanical information

The transducer is enclosed in a robust stainless steel enclosure.

Technical parameters

Type of measurementliquid level (from pressure difference)
Maximum measurement range0 to 600 meters
Best measurement precision0.1% of measured range
this combined precision accounts for non-linearity of measurement, hysteresis and repeatability
Long-term drift
Recommended calibration frequencyonce every two years
Measured medium temperature-40 to 60C
Power supply5V - 28V DC
Communication4-20mA output; MODBUS RTU; SDI-12
IP protection grade according to (IEC 60 529) EN 60 529IP 68


Testing applications and SDK and integration tools are promptly available on request via

Label description

Information included on the label:

  • Manufacturer
  • Full order code
  • Measurement range and precision
  • Serial number
  • IP rating


Order shall contain the following information:

  • Date and reference order number
  • Name and address of customer (including VAT number where appropriate)
  • Order code assembled from order tables including number of units and requested delivery date
  • Type of shipping
  • Optional extras to include (for example calibration certificates)

Order code table

Measurement range (M)
M00 - 0.25m
M10 - 0.5m
M20 - 1m
M30 - 2m
M40 - 4m
M50 - 8m
M60 - 10m
M70 - 20m
M80 - 40m
M90 - 80m
M100 - 100m
M110 - 160m
M120 - 250m
M130 - 400m
M140 - 600m
MXspecial - on request
Measurement precision (P)
PXspecial - on request
Variation (T)
T0standard / typical
T1for potentially explosive atmospheres
TXspecial - on request
Output type (W)
W1RS485 with MODBUS
WXspecial - on request


Sensors are packed individually into padded cartons.

The packaging includes all information required for proper use and servicing of the equipment.


Physical installation of the sensor

The following tables show functionalities of the pins on the sensor side of the connection for different combinations of physical connectors and transciever types.

4-20mA output
red wire:   positive
black wire: negative
Hirschmann CA3GS for RS485 (W1)

Hirschmann CA3GS (4pin) connector

Pin Function Notes
1 VCC Supply 3v3 DC to this pin
2 RS485: A
3 RS485: B
4 GND Supply GND to this pin
Hirschmann CA6LS for RS485 (W1)

Hirschmann CA6LS 7 pin connector

Pin number Function Notes
1 VCC Power supply to sensor - keep powered for autonomous measurements and archiving
3 RS485: A
4 RS485: B
5 keep not connected
6 WAKEUP Pulling low (to GND) wakes up the sensor for communication. Permanently wire to GND to disable sleep.
7 keep not connected

MODBUS implementation

Default RS485 configuration: 38400 baud, 8N1 ( => 1 start bit, 8 data bits, 1 stop bit, no parity)

Default communication protocol: MODBUS - implementation information: ML MODBUS version 1

Design and manufacture

For support please contact your distributor or manufacturer directly via