Hydrostatic Level Transmitter Selection Guide for Tanks and Industrial Liquid Level Measurement
A level transmitter normally gets attention when there is already a problem.
The tank level shown on the panel does not match the actual level. A pump is running with poor level feedback. The existing sensor has failed because of water entry. Or a new project needs continuous level measurement, but the engineer has to decide between ultrasonic, float, pressure based and other technologies.
For tanks, sumps and similar liquid applications, a hydrostatic level transmitter can be a practical option when continuous level measurement is required from inside the liquid.
The Radical TechArt liquid level transmitter shown in the supplied PDF uses a compact stainless steel submersible probe connected through a long cable. The supplied model is designed around continuous electrical level measurement rather than simple high or low level switching.
What Is a Hydrostatic Level Transmitter?
A hydrostatic level transmitter measures liquid level by detecting the pressure created by the liquid column above the sensing point.
In practical installation, the sensing probe is lowered into the tank or sump. As the liquid level rises, the pressure acting on the sensing diaphragm increases. The transmitter converts that measurement into an electrical signal that can be sent to an indicator, controller, PLC or other monitoring system.
That makes it fundamentally different from a float switch.
A float switch normally provides a switching point such as high level or low level. A hydrostatic transmitter is used when you want to know how much liquid is actually present across a measuring range.
The product shown in the PDF is a cable suspended, submersible liquid level transmitter with a stainless steel sensing body.
Why This Type Makes Sense in Actual Tank Applications
For many tanks, getting a good measurement from above is not always convenient.
There may be foam on the surface. The top of the tank may have limited mounting space. The vessel may be underground. A sump may have no practical location for a conventional top-mounted instrument.
A submersible transmitter approaches the problem from the opposite direction. Instead of trying to detect the surface from above, the probe sits in the liquid and measures from below.
This can make installation straightforward in applications such as:
- Water storage tanks
- Underground tanks
- Sumps
- Sewage and wastewater collection points
- Reservoir monitoring
- Utility water systems
- Pump control systems
- General non-corrosive liquid storage
The important point is that the transmitter still has to match the liquid, level range, cable length and control-system input. The technology alone does not guarantee a good installation.
The Radical TechArt Liquid Level Transmitter
The supplied PDF shows a cylindrical stainless steel submersible transmitter approximately 25 mm in diameter and 107.5 mm long. The illustrated configuration has a 0 to 2 metre adjustable measuring range and a 5 metre cable as the default configuration.
Best for:
Continuous monitoring of compatible non-corrosive liquids where a submerged probe can be installed directly inside the tank, sump or reservoir.
Why this model makes sense
One useful feature is the choice of output signals.
The PDF lists 4 to 20 mA as the default output, with 0 to 10 V, 0 to 5 V and RS485 also listed as options. This means the transmitter can be selected around the receiving instrument rather than forcing every application into one signal format.
For a conventional industrial control panel, 4 to 20 mA is often the straightforward choice when the PLC, indicator or controller already has an analog current input.
RS485 becomes relevant when the intended monitoring architecture uses compatible digital communication.
The PDF also lists a 12 to 36 VDC supply, with 24 VDC stated as typical, which fits naturally with the 24 VDC instrumentation power commonly available in industrial panels.
Construction Details That Matter More Than They Look
A submersible transmitter lives in a much harsher environment than a panel-mounted instrument.
The probe is continuously exposed to the liquid. The cable may remain wet. Cable joints can become failure points. Water ingress can destroy otherwise good electronics.
That is why construction details deserve attention.
316L stainless steel isolation diaphragm
Page 2 of the PDF specifically highlights a 316L stainless steel isolation diaphragm. The document positions it for different measurement media and mentions configurable construction according to application requirements.
This should still not be interpreted as universal chemical compatibility. The PDF separately specifies the measuring medium as liquid that is non-corrosive to stainless steel. Material compatibility should therefore be confirmed against the actual process liquid before ordering.
IP68 protection
The product information highlights an IP68 protection level for the probe. For a submerged instrument, this is an important specification because the sensing assembly is expected to operate while immersed.
Cable construction
Page 3 describes a polyurethane cable with a non-corrosive PTFE protective layer, intended for longer service life. Because the cable is part of the level measurement assembly, cable material and installation condition should not be treated as an afterthought.
Diffused silicon sensing element
The same page identifies a high-precision diffused silicon core and digital circuit design. The PDF also highlights integrated laser precision welding and a one-piece structural approach intended to improve sealing.
Lightning and surge protection
Page 2 additionally highlights upgraded lightning protection, including references to air self-discharge, surge absorption and transient suppression protection. This can be particularly relevant when level transmitters are installed in exposed outdoor tanks or remote locations.
Key Technical Specifications
| Parameter | Available PDF Specification | What It Means for Selection |
|---|---|---|
| Measuring range | 0 to 2 m, adjustable | Match the transmitter span to actual liquid depth |
| Output | 4 to 20 mA default, 0 to 10 V, 0 to 5 V, RS485 | Select according to PLC, controller or monitoring input |
| Supply | 12 to 36 VDC, typical 24 VDC | Suitable for common DC instrumentation panels |
| Accuracy | 0.5% FS default, 0.2% FS listed | Choose according to required measurement precision |
| Stability | ±0.1% FS/year | Indicates stated long-term performance |
| Temperature drift | ±0.02% FS/°C | Relevant where liquid temperature varies |
| Overload | Less than 1.5 times range | Avoid subjecting the probe to excessive pressure |
| Materials | Rubber, 304 SS, 316 SS | Confirm compatibility with process liquid |
| Standard cable shown | 5 m | Cable length must suit tank depth and panel location |
These values come from the product parameter table on page 4 of the supplied PDF.
One specification deserves confirmation before purchase. The document prints the medium-temperature entry as “0-50%°C”, which is not a clear engineering range. The exact allowable liquid-temperature range should therefore be confirmed from the supplier or final datasheet rather than assumed.
4 to 20 mA, Voltage or RS485: Which Output Should You Select?
This is where many buyers focus on the sensor but forget the receiving system.
Choose 4 to 20 mA when:
You have a PLC, level indicator, controller or acquisition system with a compatible analog current input and want a conventional industrial measurement loop.
The PDF also shows a dedicated two-wire current output wiring arrangement.
Choose voltage output when:
Your controller or acquisition device specifically requires a 0 to 5 V or 0 to 10 V input.
Do not assume that a PLC analog input accepts every voltage and current standard. Check the input card first.
Consider RS485 when:
The receiving system has compatible digital communication capability and RS485 is part of the intended architecture.
The PDF shows separate wiring for the RS485 version, reinforcing that wiring and output configuration must be selected together.
Where Hydrostatic Level Transmitters Are Commonly Used
Water storage tanks
A straightforward use case when continuous tank level has to be shown on a panel or control system.
Underground tanks
Because the probe enters the liquid directly, an underground installation does not necessarily require a large top-mounted measurement instrument.
Sumps and pump systems
Continuous level feedback can be used by the surrounding control system to monitor liquid level and support pump operation.
Wastewater applications
The PDF specifically positions the product around sewage duty on page 1. Actual wastewater suitability should still be checked against solids, sludge buildup and material compatibility.
Reservoir and remote water monitoring
Submersible level measurement can also be useful when the measurement point is away from the control panel, provided cable length, signal transmission and electrical protection are properly planned.
Common Selection Mistakes
| Do This | Not This |
|---|---|
| Select the measuring range from actual maximum liquid depth | Order a random standard range |
| Confirm liquid compatibility with stainless steel | Assume every liquid is suitable |
| Match 4 to 20 mA, voltage or RS485 to the receiving system | Order the transmitter before checking the PLC input |
| Calculate required cable length before purchase | Extend the cable casually at site |
| Keep wiring joints dry and protected | Leave extension joints in a wet location |
| Confirm the exact operating temperature | Rely on an unclear catalogue temperature entry |
| Plan electrical grounding correctly | Treat shielding and grounding as optional |
| Check installation depth and probe position | Drop the sensor anywhere in the tank |
Installation Point Buyers Often Miss
Page 5 of the PDF contains an important wiring note: the shielded wire and marked grounding point should be effectively grounded. It also states that if an extension cable is installed, the wiring portion should remain dry and ventilated.
That matters because a cable extension located inside a wet junction point can defeat the benefit of using an IP68 submersible probe.
The document also states that reverse-connection protection applies to the current-output version, while reverse connection of other output types can damage the transmitter. Wiring should therefore be verified against the selected output before energising the instrument.
Quick Selection Checklist
Before ordering a hydrostatic level transmitter, confirm:
- What liquid is being measured?
- Is it compatible with the probe and diaphragm materials?
- What is the actual maximum liquid depth?
- What measuring range is required?
- How much cable length is required from the probe to the termination point?
- Does the receiving device require 4 to 20 mA, voltage or RS485?
- Is 24 VDC or another suitable DC supply available?
- What accuracy is actually required?
- What is the real liquid temperature?
- Will any cable joint remain dry and properly protected?
- Is grounding planned correctly?
- Does the application require additional surge or lightning protection?
Hydrostatic vs Ultrasonic Level Measurement
Neither technology is automatically better.
Choose a hydrostatic transmitter when direct liquid contact is acceptable and a submerged measurement arrangement works well for the tank.
Consider an ultrasonic transmitter when non-contact measurement is preferred and there is a suitable mounting location above the liquid.
For a purchase team, the better question is not “Which technology is best?” It is “Which measurement principle suits this tank and this installation?”
Why Buy from Radical TechMart?
A level transmitter should not be selected from measuring range alone.
The sensor material, cable length, liquid compatibility, output signal, supply voltage and receiving control system all affect whether the instrument will work properly after installation.
At Radical TechMart, customers can get support for selecting level instruments around the actual application, along with pricing, availability and technical specification guidance.
This is particularly useful for OEMs, system integrators, maintenance teams, EPC contractors and factories that need the transmitter to work with an existing indicator, controller, PLC or monitoring system.
Final Thoughts
A hydrostatic level transmitter is a relatively simple way to obtain continuous liquid-level measurement, but the buying decision still needs engineering attention.
For the transmitter shown in the supplied PDF, the main points worth checking are the 0 to 2 metre adjustable range, selected output signal, 12 to 36 VDC supply, cable length, stainless steel construction, IP68 probe protection and compatibility with the actual liquid.
Getting those points right before purchase is much easier than solving a range, wiring or compatibility problem after the probe is already inside the tank.
FAQs
1. What is a hydrostatic level transmitter used for?
It is used for continuous liquid-level measurement in tanks, sumps, reservoirs and similar applications by measuring pressure associated with the liquid column.
2. Can this level transmitter connect to a PLC?
Yes, provided the selected transmitter output matches the PLC input. The supplied product information lists 4 to 20 mA, 0 to 10 V, 0 to 5 V and RS485 options.
3. What is the measuring range of this transmitter?
The supplied PDF lists an adjustable 0 to 2 metre range for the shown configuration.
4. Is the sensor waterproof?
The PDF highlights IP68 protection for the submerged probe.
5. What is the default output?
The product parameter table lists 4 to 20 mA as the default output.
6. What cable length is supplied?
The illustrated configuration shows 5 metres as the default wire length. Confirm the required cable length before ordering.
7. Can it be used for corrosive chemicals?
The PDF specifies measurement of liquids that are non-corrosive to stainless steel. Chemical compatibility should therefore be confirmed before use with corrosive media.
8. Can the cable be extended?
The document discusses extension cable installation but specifically says the wiring portion should remain dry and ventilated. Extension method and final cable requirement should be confirmed before installation.
