KOBOLD vs Fineherc - Optical Level Sensors: Which Is the Better Choice?
Choosing an optical level sensor sounds simple until a machine stops because a tank has run dry, or a fuel reservoir overflows during an unattended shift. At that point, the important question is no longer which sensor looks better on a catalogue page. It is which device fits the liquid, survives the operating environment, and works reliably with the existing control system.
KOBOLD and Fineherc offer two options worth considering, particularly for industrial equipment, liquid storage, and fuel monitoring. Their products share a basic sensing principle, but their published specifications, product positioning, and purchasing approaches differ.
1. How Optical Level Sensors Work
An optical level switch uses infrared light to detect whether liquid has reached a particular point. When the sensing tip is exposed to air, light is reflected back to the receiver. When liquid covers the tip, the change in refractive conditions alters the received signal and triggers an electrical output.
There are no moving floats or mechanical linkages to jam. That is a genuine advantage in compact tanks and vibrating machinery.
However, optical switches have a limitation: they normally detect a point level rather than continuously measuring the tank from empty to full. Deposits on the sensing tip, trapped air, incompatible liquids, or incorrect mounting can also cause problems. The technology is useful, but it is not magic.
2. KOBOLD vs Fineherc: The Main Differences
KOBOLD is an established industrial instrumentation supplier with a range of level-measurement products. Its OPT optical level switch is designed for transparent liquids and small vessels, while its NSD series offers another option for compatible clear, low-viscosity liquids.
Fineherc's published optical fuel level sensor is the PLS-SS101. It is positioned for fuel and oily-liquid applications, including diesel tanks, lubricating-oil systems, and industrial machinery.
The practical distinction is straightforward: KOBOLD OPT is a strong candidate for transparent-liquid point detection, while Fineherc PLS-SS101 deserves consideration when the application specifically involves fuel or oil.
Neither product should be selected on brand name alone. Compatibility with the actual liquid, output wiring, pressure, temperature, and mounting dimensions matters more than a broad marketing claim.
3. Model-by-Model Technical Comparison
KOBOLD OPT Optical Level Switch
KOBOLD publishes the following specifications for its OPT series:
Supply voltage: 24 V DC for OPT-4 and OPT-5 versions; the OPT-0 OEM version uses 5–12 V DC.
Output: NPN or PNP open-collector, depending on the version.
Maximum operating pressure: 10 bar.
Maximum operating temperature: 80°C.
Housing options: polypropylene or stainless steel, depending on configuration.
Repeatability and hysteresis: approximately ±1 mm.
Protection: IP68, according to the published datasheet.
The model suffix matters. For example, OPT-4 uses a PNP output, whereas OPT-5 uses an NPN output with a different switching function. These are not interchangeable details when connecting a sensor to a PLC.
Fineherc PLS-SS101 Optical Fuel Level Sensor
Fineherc lists the PLS-SS101 for gasoline, diesel, lubricating oil, and other oily liquids. Its published specifications include:
Supply voltage: 5–30 V DC.
Maximum operating current: 25 mA.
Response time: 8 ms or less.
Operating temperature: −30°C to +85°C.
Protection rating: IP67.
Standard overall length: 65 mm.
Standard probe diameter: 8 mm.
Standard mounting thread: M10 × 1.0.
Output: digital switching signal.
Housing: stainless steel.
Fineherc also advertises customized probe lengths, mounting threads, cable lengths, and electrical configurations.
One important purchasing detail: the PLS-SS101 page does not establish that every customized version has the same performance or approvals as the standard product. Buyers should request a model-specific datasheet and written confirmation of output polarity, switching logic, pressure rating, and fuel compatibility before ordering.
4. Price Comparison: What Should Buyers Budget?
Price is often the first question from an equipment manufacturer, but there is no universally fair comparison without matching specifications and order quantities.
KOBOLD USA lists its OPT optical level switch starting at approximately US$268. Its NSD economical optical level switch starts at approximately US$213. These are published starting prices, not guaranteed quotations for every configuration or region.
Fineherc presents the PLS-SS101 through a factory quotation and inquiry process rather than publishing a fixed unit price on the product page. Consequently, a defensible like-for-like price cannot be calculated from the published information alone.
For budgeting, request quotations at quantities of 1, 10, and 100 units. Include shipping, import duties, connectors, cable extensions, control-interface components, and any sample-testing costs. A lower sensor price may be attractive for high-volume OEM production, but savings disappear quickly if additional interface hardware or repeated replacements are required.
Installation cost is equally application-dependent. A replacement sensor fitted to an existing threaded port may require little more than isolation, removal, sealing, wiring, and functional testing. A new installation can require tank drilling, fabrication, wiring, controller programming, and leak testing. Obtain a site-specific estimate instead of assuming that installation is free.
5. Installation Difficulty and Everyday Performance
For a typical KOBOLD OPT installation, first verify the correct thread, sealing arrangement, supply voltage, and NPN/PNP output. The manufacturer's instructions warn against positioning the sensing tip downward, because droplets remaining on the lens can affect switching.
Fineherc's PLS-SS101 uses a standard M10 × 1.0 threaded configuration, with other mounting options available by customization. Before drilling a tank, check the wall thickness, available clearance, probe immersion depth, seal compatibility, and cable routing.
Consider a diesel generator in a remote equipment room. A low-level signal could alert the controller before the fuel supply is exhausted. In this situation, the PLS-SS101's fuel-oriented design may make it a logical candidate, provided its electrical and environmental ratings are verified.
Now consider a compact water reservoir in a vending machine or process unit. If the liquid is clear and the installation falls within its pressure and temperature limits, KOBOLD OPT may be a sensible choice.
In both cases, test the sensor in the real liquid before committing to a large production run. Oil additives, cleaning chemicals, deposits, and temperature changes can make laboratory assumptions unreliable.
6. Which Sensor Offers Better Value?
Choose KOBOLD OPT when its transparent-liquid operating principle fits the application, its published documentation meets the engineering requirements, and local support or established procurement channels matter.
Consider Fineherc PLS-SS101 when monitoring fuel or oily liquids is the priority, a compact stainless-steel probe is suitable, and customization or factory-direct sourcing could benefit the project.
For either supplier, request written confirmation of the precise model's specifications. Do not assume an optical sensor is suitable for every opaque liquid, high-pressure tank, or hazardous area. In particular, a claim that a sensor can be customized for explosion protection is not a substitute for the required certification for the finished installation.
Insurance discounts should not be assumed either. A level alarm may support a broader risk-management plan, but any premium reduction depends on the insurer, policy wording, and documented risk controls. A sensor alone does not guarantee a discount.
Frequently Asked Questions
Is KOBOLD OPT suitable for diesel?
KOBOLD OPT is specified for transparent liquids. Confirm compatibility with the exact diesel formulation and operating conditions before use; do not assume that all fuels are suitable.
Can Fineherc PLS-SS101 measure the entire fuel level?
It is a point-level switching sensor. Multiple sensors at different heights can provide several level thresholds, but continuous level measurement requires a different system.
Which sensor is faster?
Fineherc publishes a response time of 8 ms or less for the PLS-SS101. KOBOLD's OPT datasheet lists approximately 50 microseconds for a rising level and 1 second for a falling level, depending on viscosity. These figures describe different switching conditions and should not be compared as if they were identical tests.
Which is cheaper?
KOBOLD publishes a starting price for OPT. Fineherc requires a quotation for PLS-SS101. Ask both suppliers for equivalent quantities and configurations before deciding.
Does either sensor eliminate maintenance?
No. Solid-state construction removes moving parts, but periodic inspection and functional testing remain important, especially where deposits or contamination may affect the sensing tip.
Final Verdict
There is no universal winner in the KOBOLD vs Fineherc comparison. KOBOLD OPT is a credible option for suitable transparent-liquid applications, while Fineherc PLS-SS101 is worth evaluating for fuel and oil monitoring where compact installation and customization matter.
If you have the budget, spend a little time validating the actual liquid, wiring, and mounting arrangement before purchasing hundreds of units. If the budget is tight, a sample test is still cheaper than troubleshooting a failed production line.
Ultimately, the best optical level sensor is not the one with the longest feature list. It is the one that gives the right signal under real operating conditions, so an unattended machine can keep doing its job without an expensive surprise.
