In this chapter you find answer to frequently asked questions (FAQ) about HAENNI products and their application. If your inquiry via the FAQ is not answered, you can contact us via e-mail: firstname.lastname@example.org
〉Why to use HAENNI products?
Because the HAENNI products...
1. ...are light. The weight of a standard scale is around 17 kg. A complete set (2 scales, processing unit, cabling and levelling mats) are below 100 kg.
2. ...are insensitive to temperature. They have a wide temperature range of -20 ... 60 ° C.
3. ...are reliable instruments that are insensitive to ambient conditions.
4. ...are the thinnest on the market of certifiable systems. You have a very low height in relation to the nominal load.
5. ...have a large "active" measuring surface. New products are fully traversable.
6. ...adapt their flexible design optimally the ground and guarantee optimal area distribution of the load and prevent damage to floors.
7. ...are insensitive to uneven surfaces.
8. ...are overload protected. By force shunts during the exposure limits are exceeded, the sensing elements are not overloaded.
9. ...live long. The first wheel load scales with serial # 1 is still in operation! If despite this, anything defective, the component can be easily replaced.
Application errors & Accuracy
〉Why levelling is necessary in mobile weighing?
Without levelling out multi axle systems the suspension of the axle currently on the scale platform gets compressed. Depending on the suspension system the axle load may be higher compared to the situation on level ground. This error is cumulative. More details are available in P 1196, which may be downloaded in the section "Technical Reports". Lit. info: P 1196
〉How big is the error if weighing without levelling?
In the worst case if weighing a multi axle system the error can be as high as 1000 kg per axle! No levelling is needed for weighing 2 axle vehicles only! More details are available in P 1196, which may be downloaded in the section "Technical Papers". Lit. info: P 1196
According to OIML Class 4, depending on the division, roughly said 0.5 % full scale. More details are available in the data sheet which may be downloaded in the section "Data Sheets". Lit. info: Please refer to the data sheets accordingly
〉How accurate is the weighing of a vehicle (axle weight, gross weight)?
Additional errors may occur beside the error of the scale itself which usually are negligible. They are caused by the application and called external errors. 2 axle vehicles are causing almost no external errors. Vehicles with 3 or more axles may cause additional errors which may be definitely higher than the error of the scale itself! Refer also to "levelling".
〉Is a scale with a lower division (e.g. 20 kg instead of 50 kg) more accurate?
Yes, but the better accuracy applies only to the scale itself! All external errors remain the same There is an advantage only if the scales are used on perfect ground and if the same number of scales as wheels is used (weighing a vehicle in one operation)!
〉What means OIML?
OIML is the abbreviation for Organisation Internationale de Métrologie Légale. In most countries of the world the recommendations of OIML are the basis for the national law for scales.
Accessories & Manpower
〉Does it need much accessories, like ramps, wedges, etc.?
No! All fits easily within the trunk of a passenger car. No component is heavier than 17 kg. Lit Note: Datasheet W9.100
〉Which accessory is available HAENNI?
Levelling mats to prevent from errors when weighing multi axle systems, Mounting frames for semi fixed installations, remote displays, carrying cases, cables chargers and much more! Lit. Note: Datasheet W9.100
〉What is the set-up time till the first vehicle may be weighed?
The minimum configuration is set up within approximately 2 minutes. About 10 minutes are needed for setting up a full system comprising mats and processing unit as it is used for weighing a big quantity of vehicle in a short time. See also our video on YouTube.
〉How long does it take to weigh a vehicle?
Static scales: It is possible to weigh 30 trucks with 5 axles within one hour including the printing of the weighing protocol. That means 2 minutes per truck only! In general one should calculate rather 5 minutes per truck. Dynamic scales: At 5 km/h a 20 m truck passes the system within 15 seconds! Additional time is required for operating the system. Therefore in practice one can calculate with 20 to 30 seconds per vehicle. See also our video on YouTube.
〉How much personnel is needed?
One person is sufficient. This could even be the driver of the truck himself. In normal application it is favorable to work with two persons. See also our video on YouTube.
〉What can be weighed?
In principle, anything that rests on air filled tires that fit within the platform can be weighed provided the tire is not inflated to or produces a pressure on the platform of the scale that exceeds 170 psi.
〉What is the lifetime of the HAENNI scales?
Properly used the HAENNI scales are lasting for more than 20 years. Exposed parts may wear out with the years, but never the measuring system itself!
〉What are the requirements for the weighing site?
The low profile scales are designed for the use on firm and smooth surfaces like tarmac or concrete.
〉What happens if HAENNI low profile scales are used on unsuitable ground?
With time the base plate gets bent if used on uneven surfaces but the measuring properties are not affected! When using the scales on surfaces where gravel is present the weighing site should be cleaned before placing the scales. If this is not feasible the scales may be ordered with a rubber coated base plate which avoids such deformations! If used on unstable ground (like dirt or forestry roads) the base plate may be deformed after few weighing only!
〉HAENNI low profile scales are very thin. Do they therefore deform easily?
No! HAENNI scales are known as very robust. No damage will occur provided they are used on fairly smooth and level ground. Even if used on very rough surfaces no damage will occur provided that the scales are fitted with the optional rubber coated base plate.
〉Is it possible to overload HAENNI low profile scales?
Static scales WL 101 and WL 103: No damage will occur as long as the applied load remains below the over load limit specified in the data sheet which for most ranges is 25 % higher than the nominal capacity. Concentrated loads as hard rubber wheels or rigid items may cause a wrong reading but in any case no damage!
Dynamic scales WL 110: Only a load concentration as it is typical for hard rubber or metal wheels may cause damage. Even the biggest overload will cause no damage as long as the concentration is below the limit specified in the data sheet.
〉What are the limitations for storing and transporting HAENNI Wheel Load Scales?
Only the storage temperature as per the data sheet, generally -30...+60°C, must be respected. Shock and vibrations are no issue as long as the scale does not fall onto a hard ground from more than 20 cm.
〉Is it possible to calculate goods prices based on the weighing result?
In principle no. Mobile scales are not allowed for trade because additional errors may occur if not used properly. This is to avoid fraud. Exceptions are possible if both parties, the vendor and the purchaser, agree upon the use of mobile scales.
Weighing in motion
〉Is weighing in motion exactly the same procedure as static weighing?
No. In addition to the measurement error of the scale itself (usually negligible), errors may occur through the practical application (external fault). These are larger in the dynamic measurement by factors! Both, the condition of the vehicle as well as the quality of the ground have a decisive influence on measuring accuracy. Lit. info: P 1215 + Lit. info: P 1216
〉Where are dynamic scales preferably used?
Dynamic sales as the WL 104 are preferably used for the pre selection. This makes sense, if a 100 % control of vehicles is aspired and the performance has to be increased. In addition to that quickly dynamic weighing checks can be done. Especially for heavy load transports, this is an interesting option. Lit. info: P 1215 + Lit. info: P 1216