In this section we have collected some answers to the questions we receive most often. Before requesting direct assistance please kindly check that your question has not already been reported and solved in this section.
The cause could be:
Electrical cause: you may have reversed the polarity of the signal or power supply conductors of the load cell.
Solution: check the connections by comparing the load cell data sheet with the wiring diagram in the instrument manual.
Mechanical cause: you may have reversed the direction of load of the load cell.
Solution: check the direction of load that delineates the direction in which the load cell has to work. You can find it indicated on the load cell by an arrow.
This is the most common case of a malfunction in a weighing system and could be due to a calibration error or a mechanical problem.
Here are the tests you can run to identify the problem and find the solution:
There are different procedures depending on the situation and the type of zero-setting to be carried out.
We've described 4 different types of zero-setting and the situations in which it's most appropriate to use them in this blog article: Calibrating weighing systems: the different types of zero-setting.
No. If the battery goes dead, the only data that are lost are the date and time, which will then have to be reprogrammed.
All the remaining parameters are stored in non-volatile memory.
If the load cell is connected to a multichannel weight transmitter or an intelligent junction box with built-in diagnostics, the malfunction of the load cell is signaled directly by the instrument.
If instead you want to run a more thorough test with the digital multimeter and measure the resistance and voltage values of the load cell, we've collected all the steps in this blog article in detail: How to check if a load cell is working correctly – Test with digital multimeter.
Yes, all our load cells are compatible with weight indicators and transmitters from any manufacturer, which have mV / V input for strain gauge sensors.
On the other hand, all of our weight indicators are compatible with strain gauge cells from any manufacturer.
The 6-wire load cells have two extra wires called “reference” (Sense + and Sense –) that are used to measure and adjust the actual voltage reaching the load cells.
Thanks to the references, the 6-wire load cells can compensate for a voltage drop, e.g. due to temperature changes or cable length, without affecting weight measurement.
For this reason, if necessary, their cable can be shortened without damaging the load cell, while bearing in mind that making a modification to the original product involves the loss of the warranty.
The 4-wire load cells, on the other hand, are calibrated and thermally compensated in relation to the length of the cable with which they are supplied as standard.
That is why we recommend that you never shorten the cable: this could compromise the reliability of the calibration and compensation.
If possible, it should be inserted into the cable duct by itself and laid as far away as possible from the power cables.
In addition, in order to limit a voltage drop in the portion of the cable between the junction box and the weight indicator, it is recommended to use a shielded cable with a significant cross-section (at least 1 mm2).
No, because UL certification for a load cell is not necessary.
UL regulations refer to the safety of electronic instruments. The mark indicates that the instrument has been tested to ensure that the user does not get electrocuted or receive an electric shock.
However, UL considers load cells to be an ultra-low voltage device (less than 50 VAC or 75 VDC) with very low current, so the risk of electrocution is de facto non-existent.
You can choose from several programs:
To help guide you in making your choice, we've gathered the details of all the features and operating principles of the different firmware in this blog article: Features and operation of LAUMAS firmware.
With a weight indicator equipped with a MULTI program, the installer can independently select the type of software desired, in order to meet multiple needs.
Consequently, the dealer who decides to have this type of indicators in stock will have available “wildcard” instruments capable of adapting to the different supply needs that may arise.
To find out about all the programs that you can select with the MULTI software, read the blog article: Features and operation of LAUMAS firmware.
Yes, with the W-series weight indicators you can view the weight on two different instruments and manage the weighing system from two separate locations using the weight reading mode via serial port.
Simply connect one of the two weight indicators to the load cells and transfer the measured weight to the other weight indicator, via port RS232 or port RS485.
In this way, the second weight indicator becomes independent, as if it were also connected directly to the load cell system.
The procedure to enable this function is described in the “Reading the weight via the serial port” section in each instrument’s manual.
Yes, all W-series weight indicators and LAUMAS weight transmitters have a theoretical calibration procedure that allows calibration to be carried out by simply setting the load cell data in the instrument's menu.
You can watch how to calibrate a LAUMAS instrument in the tutorial: Calibrating weight indicators and weight transmitters.
You can check out our specific tutorials on this topic:
Yes, almost all LAUMAS weight indicators and weight transmitters can be managed from a PC via the free Instrument Manager software.
The software makes it possible to configure parameters, monitor, perform true calibration and update our instruments.
Read more about Instrument Manager and download it for free.
In a video and a blog article we have collected all the norms and tips on how to properly install a weighing system.
The video is also available in 8 short tutorials, each of which answers a specific technical question.
Watch the full video below, or click on the question that best describes your concern and you'll find the detailed answer in our blog, accompanied by a reference tutorial.
Your most frequently asked technical questions:
1. How do you install load cells correctly?
2. I need to install single-point load cells for platforms. What should I pay attention to?
3. If there are any connecting pipes in the structure to be weighed, how do I limit friction that can affect weighing accuracy?
4. How do I check if a load cell has been installed correctly in a weighing system?
5. How to connect multiple load cells in parallel? What characteristics should the extension cables used for the connection have?
6. How to do welding with load cells already fitted?
7. When is it necessary to make and place constraints on the structure to be weighed to counteract lateral forces and the danger of overturning?
8. When weighing silos, tanks or structures with legs, what should I pay attention to?
9. How do you make a proper earthing system that prevents electrostatic charges from passing through the load cells and damaging them?
10. How to install weight indicators and transmitters in a weighing system correctly?
In this case, the weighing instruments must be calibrated on a periodic basis that is established by the company in agreement with the Quality Inspector, also depending on the intended use.
If the instrument plays a fundamental role in the company production process and the frequency of its use is high, the checks can be monthly or half-yearly.
If, on the other hand, the instrument is used for marginal activities and with low frequency, the checks may be more extended over time, for example every 24 - 36 months.
The verification is carried out using calibrated sample weights, referable to national or international samples.
LAUMAS has a worldwide network of service centres capable of carrying out calibration reports that can be used in an ISO 9001 system.
For information on the closest service centre, fill out the form.
A non-automatic weighing instrument (NAWI) is an instrument that requires the intervention of an operator during the weighing process.
European Directive 2014/31/EU requires the use of non-automatic weighing instruments complying with the Directive for the following use categories:
Before being put into service, instruments for legal for trade use must undergo a conformity assessment and other periodic checks over time.
The checks are carried out every three years for Italy, while for the other Member States of the European Union the frequency is determined by the single national laws.
We can carry out the first check for NAWI (CE-M) on LAUMAS weighing instruments both at our headquarters and on site through our network of support centers, in accordance with Directive 2014/31/EU.
According to this Directive, conformity assessment is necessary if the weighing system is used in applications for legal for trade use or for medical, pharmaceutical, judicial or sanctioning purposes (see FAQ No.21).
For subsequent checks (periodic checks), it is necessary to contact an accredited bodyin the area.
In Italy, the periodic checks are carried out every three years starting from the date of conformity assessment, while for the other Member States of the European Union the frequency is determined by the single national laws.
An automatic weighing instrument is an instrument that determines the mass of a product without the intervention of an operator.
Its characteristic is to follow a predetermined program of automatic processes.
For commercial use, such instruments must comply with the requirements stated in Directive 2014/32/EU, in particular:
LAUMAS provides weight indicators (W series) and weight transmitters (TLB and TLB4) that comply with the Directive and are certified as “MID transmitters” for gravimetric filling machines (TLB4 also for catchweighers). In order to compose a weighing system certified as a complete MID device, the weight transmitters will have to be connected to other devices and the whole assembly will have to be certified.
Here is a list of the main automatic weighing instruments that must meet the OIML (International Organization of Legal Metrology) requirements and recommendations:
From the PRODUCTS menu, select the product whose documentation you are looking for.
On the dedicated web page, in the DOWNLOAD section there are flags through which you can check which documents are available in the different languages.
Click on your language to have access to all the available documentation for the selected product.
To download a manual you must first be registered on the website, with quick or full Registration: you can do it here.
After logging in, select the Menu SUPPORT AND DOWNLOADS > DOWNLOADS > Manuals and Data Sheets.
On this page you can search for and download manuals and data sheets for all our products.
Alternatively, from the PRODUCTS menu, select the product whose documentation you are looking for.
You will also find reference manuals on the dedicated web page in the DOWNLOADS section.
To download software or a configuration file you must first be registered on the website, with quick or full Registration: you can do it here.
After logging in, select the Menu SUPPORT AND DOWNLOADS > DOWNLOADS > Software and configuration files.
On this page you can search for and download the software/configuration files of the instruments that require them, as well as the Instrument Manager supervision software.
Alternatively, from the PRODUCTS Menu > ELECTRONIC INSTRUMENTATION, select the instrument you are interested in.
You will also find the reference configuration file on the dedicated web page in the DOWNLOADS section.
To download a product’s CAD drawing you must first be registered on the website, with quick or full Registration: you can do it here.
After logging in, select the Menu SUPPORT AND DOWNLOADS > DOWNLOADS > CAD Drawings.
On this page you can search for and download all the available CAD drawings for our products.
Alternatively, from the PRODUCTS Menu, select the product whose drawing you are looking for. If available, you will find it in the DOWNLOADS section of the dedicated web page.
Test certificates are always provided together with the products purchased.
If you need a duplicate, you can request it by opening the specific support ticket.
After logging into the website, from the SUPPORT AND DOWNLOADS Menu, under the SUPPORT category, select Test certificates duplicate and fill in the Ticket.
To download a product certificate (metrological certifications, certifications for areas with an explosion hazard or other certifications) you must first be registered on the website, with quick or full Registration: you can do it here.
After logging in, select the Menu SUPPORT AND DOWNLOADS > DOWNLOADS > Certificates.
On this page you can search for and download all the available certificates for our products.
Alternatively, from the PRODUCTS Menu, select the product whose certificate you are looking for. You will find it in the DOWNLOADS section of the dedicated web page.
A load cell is an electronic component (transducer) to which a weight force is applied.
The load cell is able to convert the weight force applied into an electrical signal in mV proportional to the mechanical deformation expressed in tenths of a millimetre caused by the same force.
A load cell consists of a metal body (stainless steel or aluminium) to which strain gauges are applied. The strain gauges are constituted by a grid of thin metal wire (constantan) applied to a support of insulating material and glued into specific areas of the load cell. The strain gauges follow the deformations of the surface of the load cell to which they are bonded, lengthening and shortening along with it; these dimensional changes cause a variation in electrical resistance, which through the "Wheatstone Bridge" connection, is converted into a proportional electric signal normally expressed in mV (thousandths of a volt).
Depending on the type of application for which they have been built, or the construction method used, we mention some common types of load cells that LAUMAS can offer you: