Non-contact measurement with light

Kopfbild Start 960x280 VLM500 en
VLM500-MIDThe new VLM500-MID for verified length measurement tasks

If measuring instruments are used in the public interest or in commercial or official traffic, the German law Mess- und Eichgesetz (MessEG), must be considered. For the purpose on the harmonisation of the laws of the Member States relating to the making available on the market of measuring instruments the European parliament adopted the Measuring Instruments Directive (short MID) 2004/22/EC and 2014/32/EU respectively.

In the sense of a type approval, the devices of the VLM500 series are considered as counters. So they are part of a length measuring device. A type approval for the counter itself cannot be obtained. Rather, an independent examination must be considered with the aim of being able to offer a pre-tested counter (certified by a parts certificate) on the market. In this case, customers are the manufacturers of length measuring machines that require a non-contact counter for their system. The examination was carried out successfully by ASTECH GmbH together with the German Physikalisch Technische Bundesanstalt (PTB). The exam consists of a theoretical and a practical part. Conformity to the software guide WELMEC 7.2 and fulfilment of the metrological properties of the MID have been certified.

The VLM500-MID consists of two units, the measuring device VLM500 and the display and storage unit CDB. Both are connected by a cable (length up to 15 m). The VLM500 is available in the existing variants A, D, L and E and can be equipped with optional pulse outputs (encoder signals), one analog output or field bus interfaces (Profinet or EtherNet / IP). The internal software deviates from the software of a standard VLM500 only in terms of the requirements for the WELMEC 7.2. Deviating from this is that the programming interface is only indirectly accessible. Due to the wiring, the VLM500 is parameterized via the CDB.

To conform to the gauge requirements the VLM500-MID is equipped with seals and leadings. The connection cable between VLM500 and CDB, for example, must not be removed in the safe operating mode. To ensure this inseparability, the screw connections are provided with a seal. In addition, the housing covers are provided with special screws that allow the attachment of a sealing thread and a leading. Parameter changes to the devices can only be made if a special programming adapter is connected to the CDB. Then the system is in unsecured mode. But since the plug for the adapter is also sealed, the parameterization should be carefully considered before the system is backed up.
VLM500-DGNEW - VLM500-DG for skin pass leveling applications

For the first time ASTECH presents an integrated system solution to measure and calculate the skin pass level and the extension ratio – important parameters to control rolling mills in the steel or non-iron industry. The basic VLM500-DG system is a master-slave combination, consisting of two velocity measuring gauges from the ASTECH VLM500 series. This system communicates the measured skin pass level to a programmable controller via Profinet or EtherNet/IP.

The VLM500-DG system determines the skin pass level from an internal length measurement algorithm which considers all and even the smallest velocity fluctuations. The VLM500-DG system consists of one master and one or two slave VLM500 gauges. The master controls the measurement and skin pass level calculation. Based on the dynamics of the skin pass mill, the master can be programmed with just a few parameters. For this purpose the well-known PC program VLMTool may be used. The most important parameter is the so called update length. It determines the distance in meters between recalculation and update of the skin pass level. Cyclically, after this distance, the master triggers the slaves which send their measured distances back to the master. Based on the update length and the distances measured by the slaves the master calculates and updates the skin pass level. Master and slaves are physically interconnected by a dedicated data cable.
LDS10ANEW - Distance sensor LDS10A

With the LDS10A, the entry model of the LDM series is available from now on. As announced some time ago the new device offers an infrared LED, based on distance detection up to 40 m. The LDS10A is based on the technology of the Canadian company LeddarTech and consists of self-developed ICs and advanced signal processing algorithms.

Although the LDS10A provides an attractive price-performance-ratio, the user can rely on the well-known robustness and reliability of all ASTECH products. The sensor is made with an IP67 certified housing and a solid connector in standard format M12.
CR10NEW - Single channel color sensor CROMLAVIEW®-CR10

With the CROMLAVIEW® CR10, the CROMLAVIEW® color sensor series is extended by a single-channel color sensor. The parameterization of the sensor is very simple and is done by only three times pressing a push button. Despite the localization of the sensor in a very attractive price segment, the sensor is equipped with a very generous range of functions. In addition to a single sensor button with a LED for indicating the operating conditions, the sensor has two control inputs, which can be used to trigger the measurement and to teach-in a color value. Color values can be stored with five different tolerance values. Furthermore, a teach-in is possible in the multiteach mode, in which the tolerance value is determined solely by the presentation of several color values.

Practically relevant in the industrial environment is the setting of a key lock and the optional setting of an output holding time of 50 ms at the output. Thus, very short color pulses, e.g. in the case of very fast objects can be extended for slow PLCs. The switching output itself (24 V / 200 mA) is short-circuit-proof. A special feature is the detection and display of an output short circuit. To be able to cope with the harsh industrial environment, the sensor electronics is housed in an anodized aluminum housing. This is waterproof so that the IP67 degree of protection can be achieved. Just like the existing CROMLAVIEW® color sensors, the CROMLAVIEW® CR10 also operates perceptively (according to the color perception of the human eye) and processes the color values in the L*a*b* color space. This makes it unique in the category of single-channel color sensors in its market environment.

Firmenlauf2017ASTECH participates in local running event

For the fourth time, the ASTECH team participated successfully in the Rostock business run. Over 450 teams followed the call of the organizer.

The participating colleagues successively mastered the 3.4 km long running distance at the city harbor as a relay and enjoyed the subsequent festivities and casual networking. With its annual participation in the business run, the ASTECH team celebrates its corporate values, which are anchored in its corporate culture: team spirit, collegiality, fairness and health.

We are looking forward to joining the Rostock business run in the next year.

vlm 502NEW - VLM502 for limited space applications

Nowadays, the planning of new machines and systems is computer-aided. The entire structure is visualized with the help of 3D construction programs. By doing so, the space requirements are optimized and the accessibility or maintainability of individual assemblies (sensors or actuators) is evaluated before the plant is constructed. A different situation arises during the conversion of existing production facilities (retrofit). Here, it is often the case that space for additional components is hardly given. Either the measuring device itself or its working distance is too large. In both cases, an installation of modern non-contact sensors is more difficult, if not impossible. The ASTECH GmbH has developed the new non-contact measurement device VLM502 in order to meet applications with limited space requirements.

More information about the non-contact measurement gauge VLM502 can be found on our website

LDM41AFor more than ten years ASTECH has offered laser-based distance meters for industrial purposes. From the beginning, the LDM41A was a part of the product portfolio.
Meanwhile thousands of these gauges are used to solve applications distributed over all branches of the industry. All of them share one common purpose – an accurate and reliable distance measurement.

When ASTECH first started to sell laser distance meters right after the millennium, nobody estimated the great extent of this success story. Devices of the earlier LDM30 series were still based on the electronics of simple handheld devices. Distance gauges like those where quite hard to find even on modern construction sites. Based on market monitoring and the requirements of well-known customers from the metal industry, the successor LDM40 and finally the LDM41 were developed. With its outstanding measurement capabilities and the well-known 4-20 mA interface the new model attracted great interest on the market. Additionally, the easy handling and the consistently proven reliability made the LDM41A really successful. For customers it was now easy to realize a highly accurate reflector-less distance measurement up to 30 m onto nearly every solid surface with affordable cost. With the use of targets made of special reflectors and reflecting foils the detection range of the gauge could be extended to more than 100 m.

Application-driven development

From now on the LDM41A replaced fault-prone cable extension encoders for fill-level measurement in silos or storages. Big parts of transportation machines for steel coils or paper rolls were moved exactly to the correct position by laser distance meters from ASTECH. With overhead crane position monitoring the LDM41A established a new special field of applications. Due to the comparative phase-shift principle the LDM41A provides a distance independent measuring uncertainty. No matter if the distance is 3 m or 30 m, the accuracy of the distance measurement is always ±2 mm. During the development of the LDM41 much emphasizes were put on the reliability and a robust construction. All internal optical parts are mounted in a solid metal bracket. The massive front tube prevents the receiver from extraneous light and prevents the lenses from scratches and damages caused by the harsh industrial environment. Over the yeas more and more new application cases were added. Today there are historic buildings like castles or old churches, where
ldm winkel the LDM41A monitors unwanted movements or changes of the constructions. In combination with programmable data logging devices the LDM41 observes the roof sag of big warehouses. The same setup is used to observe a street tunnel in the south of Germany for deformations of the concrete cover caused, by surrounding rocks. Not only the robust construction and the powerful measurement principle are responsible for the success of the LDM41 on the market. With the ongoing digitization and higher grade of automation the requirement for flexible and modern ways of communication arose. Therefore ASTECH presented a flexible concept of digital interfaces to transmit the measured distance values via fieldbus to the PLC world. The LDM41P with Profibus and later on the LDM41PN with Profinet interface spread the spectrum of the distance meter series. With the LDM42 ASTECH also presented an enhanced version with a faster measurement mode.

Worldwide use

For reasons of laser safety the LDM41 is not to be used if the inner temperature goes below 0° C. Therefore there is an option with an internal temperature controlled heating and a pressure regulation element available. This enables the device to be used in outdoor applications like fill level measurements on top of a grain silo in the north of Sweden. For a higher grade of protection ASTECH offers an additional protection case made of stainless steel in IP67. ASTECH and its distribution partners helped to provide worldwide success to the LDM41 series. In Australian open cast mines the depth of drill holes for explosive charges are measured by those devices. American saw mills measure the height of wood bins with the LDM41A, Chinese aluminum plants aquire the fill level of liquid aluminum or Danish flood protection facilities determine the position of big tide gates.

ldm caseCustomer-specific solutions

With much know-how about the different applications, ASTECH becomes capable to offer custom tailored solutions. Aluminum rolling mills use very aggressive and extremely penetrating rolling lubricants. For the standard LDM41 this would lead to disintegrated gaskets and the gauges would be destroyed within short time. Together with the customer, ASTECH developed a solution where all the gaskets of the LDM41A are made of Viton which is a very resistant sealing material. With this setup the customer is able to measure the correction position and diameter of freshly rolled aluminum coils despite of the ubiquitous influence of the aggressive rolling lubricant.

All these examples show that the LDM41A and its variations don’t belong on scrap heap yet. Based on the various solved applications and all the gained experiences over the years ASTECH offers a whole system of products around the LDM41A which enables to provide solutions for nearly every thinkable Application regardless how unusual they might be.

vlm lengthoffset deIn-situ color measurement in flowing liquids
With the development of an immersion probe ASTECH meets the frequent requirements for in-situ color measurement in liquids. In chemical industry, color and color saturation of liquids is often an indicator for the concentration of a solution to be determined or indicates the state of a chemical reaction. The same applies to the analysis of water, cleaning fluids or solvents. Areas of application are, for example, the detection of dye residuals, active oxygen or suspended particles. A tee piece with 3/4“ thread connections makes it easy to connect the probe in such applications. The immersion probe is connected to a color sensor of the CROMLAVIEW® color sensor family by means of a temperature stable (up to 180 ° C) and liquid-tight reflex mode fiber cable. The combination of an adjustable measuring length (0-10mm), a 12-bit control of the illumination LED, as well as a 1:800 input sensitivity of the sensor ensures a large dynamic range.

vlm lengthoffset deVLM 500 – Comfortable distance set up of two light barriers

The latest revision of the firmware of the newest VLM generation comes with an additional parameter. Now it is possible to add an offset value to the optical noncontact measured length with a simple command called “LENGTHOFFSET”. In this manner the distance of two light barriers can be programmed directly with the help of the VLMTool. This can be done with a command input or with the parameter mask. So far an input of the light barrier distance was only possible by formatting the text output. The text output is used by the digital interfaces (USB, RS232/RS422/RS485 or Fieldbus) of the VLM500. In order to be compatible to older software revisions it is still possible to format the text output. In contrast to older models two light barriers can be connected directly to the VLM500. The 24V power supply comes from the VLM. This reduces the cable work for the customer. To adjust the new parameter comfortable with the VLMTool an update is recommended. Both device firmware and VLMTool can be downloaded from the ASTECH website under

VLM500EASTECH expands the product range for distance measurement devices with the products of the Canadian company LeddarTechTM. The new product series offers a broad range of sensors using the patented LeddarTM technology. Special data processing methods designed by LeddarTM allow the usage of diffused LED impulses instead of Lasers for the time-of-flight measurement. Thereby the new sensors provide probably the best price-performance ratio.

A big advantage of the new technology are structured receiver elements, which provide up to 16 simultaneous distance measurements with one common light source. This way of 2D distance detection works without any moving parts, which makes the sensor devices very robust and reliable. There are individually adjustable threshold values or each of the 16 distance measurements, which enable the LeddarTM sensors to detect complex forms or measure length, width or height with just one sensor. Within the LeddarTM product series there are different OEM modules or ready-to-use distance meters available.

With the LeddarTMOne ASTECH offers now a quite cost-effective OEM distance sensor module, which provides the possibility to integrate distance information into cost-sensitive electronic devices and equipment. The LeddarTMOne is able to measure the distance or to detect objects in a distance of up to 40 m with an accuracy of ±5 mm.

The flagship model of the series is the completely integrated sensor system IS16, whose industrial interfaces and robust housing make it well-equipped for harsh industrial applications. The IS16 provides 2D-distance detections with 16 segments. More information about the new products of the LeddarTM series will be shortly available on our website under .

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