DE202008004908U1 - sensor - Google Patents

Abstract

sensor
with a housing (20) in which at least one sensor element for detecting a physical measured variable and a sensor electronics is accommodated, and
with an electrical interface (30) on the housing (20) for connecting the sensor (10) to a control and evaluation unit and
with an optical interface (40) formed on the housing (20)
characterized,
in that in the region of the optical interface (40) on the housing (20) for operatively connecting the sensor (10) to an external monitoring unit (70) positioned remotely from the sensor (10), means (50) for connecting at least one light guide (60) available.

Description

The The present invention relates to a sensor according to the preamble of claim 1.

This Sensor has a housing in which at least one Sensor element for detecting a physical measured variable and a sensor electronics is included. Furthermore, on the housing an electrical interface for connecting the sensor to a control and evaluation unit and also a formed optical interface.

For example It can be with such sensors, which for a variety applications in the industrial sector are known to optical, act inductive, capacitive temperature or pressure sensors.

A frequent task with such sensors is to in addition to the actual measurement information, read out further data from the sensor and / or to communicate data to the sensor.

For example this can be diagnostic, status, parameterization and / or Act configuration data.

Especially This is significant in safety applications where Regarding the condition and the functionality of a Sensors reliable information is available and sent to a parent Unit must be routed.

This is, for example, from DE 299 00 149 U1 and DE 100 46 863 already known, in addition to the electrical interface with which the sensor can be connected to a programmable logic controller or to a bus, additionally provide an optical interface to the sensor housing.

at These known sensors, the optical information is already in close proximity to the sensor into electrical signals transformed. These electrical signals are then, for example as serial signal, often without potential separation, to one external monitoring unit forwarded. This consists Accordingly, always the risk of an electrical or EMC interference. Another disadvantage of optical interfaces, the optical signals in the immediate vicinity of the sensor convert into electrical signals, in addition to the EMC sensitivity to see that an additional external hardware with contacts for connecting an additional electrical data cable or a fixed wiring in the immediate Near the sensor is necessary. For this hardware There must be a suitable field housing.

For Solutions without optical interface are becoming more and more Contacts for connecting the corresponding electrical Lines on the sensor needed. The hardware for the interface must therefore be right from the start be integrated in the device.

So far Accordingly, although optically operating connection devices known, but the received light is each in the immediate Near the optical interface converted into an electrical signal. In addition, serial are also safe and unsafe Telegrams used at electrical or optical interfaces become known.

All in all the known solutions are prone to failure and complex in terms of equipment.

When An object of the invention may be considered to include a sensor create in which the above additional data very reliably transmitted to an external monitoring unit can be.

These The object is achieved by the sensor having the features of claim 1 solved.

advantageous Embodiments of the invention Sensors are the subject of the dependent claims and will also be described in the following description, in particular with reference to the attached figures.

Of the Sensor of the above type is inventively characterized further developed that in the area of the optical interface to the Housing for effective verbin the of the sensor with an external monitoring unit positioned away from the sensor Means for connecting at least one light guide available are.

When a first principle of the invention can be considered, the relevant additional data, such as diagnostic, Status, parameterization and / or configuration data, not more electrically, but optically to an external monitoring unit to forward and / or receive from it.

In order to coherent is another core idea of the invention to be considered, in the field of optical interface suitable means to provide for connecting at least one light guide.

As a first significant advantage of the invention, it can be considered that a data transfer transmission via optical waveguides extremely interference-resistant and reliable. In particular, the sensors according to the invention are suitable for continuous use. The data transmission via the optical waveguide is in particular insensitive to shaking of the entire sensor. This is a significant advantage, especially in robust industrial environments.

One Another advantage can be seen in the fact that for the Wiring no shielding is necessary anymore, so in this Costs can be saved.

Furthermore requires the solution according to the invention a lower one compared to electrical solutions Cost and space required for the components of the interface, for example, in a receiver of a light curtain.

Especially important with regard to already existing series of sensors, for example, with respect to certain types of housings, is also that no further connector pins are needed and that the previously used connector pins their function without restriction continue to keep.

One Advantage of the solution according to the invention exists finally also in that near the sensor no additional hardware for converting optical signals in electrical signals is necessary. Rather, it can be for the present invention, the corresponding hardware advantageous be integrated into an external monitoring unit or There are commercial converter, for example, from a Optical fiber used on a USB interface. A diagnosis For example, it can be done with a notebook or a palmtop.

With the sensor according to the invention can accordingly a serial telegram can be transmitted in real time without that this transfer eventual external EMC interference would be exposed and without this being an additional Occupancy of connection contacts or an increased cabling effort required by shielding.

One After all, the most important advantage is that the solution according to the invention subsequently or can be retrofitted and activated separately as an accessory is. This is a particularly important feature since the reading or reading of the above additional data for many tasks are only optionally required.

The optical interface, for example, by a light emitting diode or a plurality of light emitting diodes may be formed.

at a particularly preferred variant is the optical interface by a light source for an indication of the power supply educated. This must be done on the housing itself no changes are made.

at a simple execution can over the optical interface only transmits data in one direction become. The functionality can be increased in this regard be set up when the optical interface for bidirectional data exchange is.

Especially preferred is the optical interface for full duplex data exchange set up. Data can then be real-time in both directions received by the sensor or sent to the sensor.

expedient For this purpose, the light guide connected to the sensor has a plurality of optical fibers. In terms of retrofitting an additional optical connector on one as such known sensor is basically desirable that this compact and space-saving are performed can.

Helpful is here, if the means for connecting the light guide or the light guide for guiding the light at least one circular segment-shaped Have light guide. Such light-guiding elements, for example As quarter-circular-shaped ele ments are known and can be made as an injection molded part, are suitable especially good to light in confined spaces desired way to divert and distract.

in principle can be a light guide or a plurality of optical fibers with the Housing firmly connected. As for many Applications do not provide the additional or safety information in question constantly, but often only on a case by case basis must stand, is particularly preferred if an adapter is present, which releasably attached to the housing is and with the optical interface in an optical operative connection can be brought.

in principle can be on the adapter a light guide or it can there several fiber optic cables are firmly connected. For example a completely assembled fiber optic cable can be delivered, which at one end the adapter for connecting to the sensor and at the other end a corresponding connection element for connection with a monitoring unit has.

The Variability of applications can be increased If, on the adapter, means for manual Loosen and connect at least one light guide available.

in the With regard to the reliable transmission of optical data comes down to a precise and defined Positioning of the adapter relative to the optical interface at. For this purpose, the housing in the region of the optical interface preferably have a shape with which the adapter into a brought at least partially positive engagement can be.

In a simple variant, the positioning of the adapter the housing are facilitated when abutting areas on the adapter for Providing a defined positioning relative to the optical Interface are formed.

A detachable fastening of the adapter can be done in a simple Embodiment can be achieved by the adapter is fixed to the housing with a resilient clip.

These Fixation can be improved even if the adapter has a contour side having, with which the resilient clip for fixing the adapter engages.

The resilient clip may for example be a plastic part or a be curved sheet metal strip.

The Reliability of data transfer over the optical interface is also increased if the penetration of dirt particles as far as possible is reduced. For this purpose, it is useful if on the adapter and / or on the housing sealant for Sealing a coupling region in an environment of the optical Interface are available. For example, this can be done in the environment of the optical interface rubber coatings available be.

The Housing of known sensors, such as light curtains, often have the shape of an elongated cuboid on, wherein at one end face of this cuboid, the electrical interface for connecting the sensor to a programmable logic controller or a bus is arranged. Because on the front side frequently no additional space available is located, is also the optical interface preferably on a side surface of the housing. In particular, this may be one and the same light source Act, which also for a voltage or "power-on" indicator is used.

There basically for all embodiments, but especially for these variants, one possible space-saving arrangement of the components is desired, is finally a development of the invention Sensor advantageous in which the adapter is shaped and formed is that he is in a state connected to the housing at least in one spatial direction does not protrude beyond the housing. Particularly preferred in this context, if the adapter is formed so that it is in one connected to the housing Condition only in one spatial direction over the housing protrudes. This can be realized with the resilient clip described above which, for example, like a "C" around the housing with the adapter goes around. The clip reaches over the Adapter and is in a suitable training, for example as resilient metal strip, in only a very small amount over the top, on which the adapter is arranged, the opposite Bottom and a side surface over. The adapter however, with appropriate training and design, it is only possible at the top of the sensor housing over, so a side where the optical interface with an optical Windscreen is formed.

in principle it would also be possible to form a parenthesis like this that this is anchored only on the side surfaces, for example when the bottom of the housing is to be kept free. In doing so, special measures must be taken to prevent that the clip jumps off. In the case of the elongated cuboid housing may for example be preferred be that the adapter is placed on top and the rest with regard to the other side and front surfaces not over the sensor housing protrudes.

Further Advantages and features of the sensor according to the invention will be described below with reference to the attached figures described.

Here in shows:

1 a schematic partial view of an embodiment of a sensor according to the invention;

2 : a view of an end face of the sensor 1 with remote light guide;

3 : a view of the front of the adapter 1 with remote light guide;

4 : a side view of the adapter 1 with removed light guide and

5 : a top view of the adapter 1 with removed light guide

An embodiment of a sensor according to the invention 10 will be related to the 1 to 5 explained. Equivalent components are given the same reference numerals in all figures.

In the example shown, the sensor is 10 to a receiver of a light curtain or light grid, in an elongated cuboid housing 20 is housed. At one end 24 , in the 2 is shown, the housing has 20 an electrical interface 30 on, over which the sensor 10 can be connected to a programmable logic controller or a bus system. The electrical interface 30 is enclosed by an M12 connector on which a connector can be screwed on. Since at the electrical interface all the plug contacts, sometimes even with double functions, are occupied, is a cable-based interface, such as a cable-based RS-485 interface, not avail available. Due to the limited space available, there is no room for another connector on the front. Even on the existing motherboard would be extremely limited space for the interface in question with appropriate Nebenbeschaltung.

The solution according to the invention essentially comprises an already existing optical interface 40 , which is not shown in detail in the figures, to use to extract desired additional information, such as diagnostic, state, parameterization and / or configuration data from the sensor and / or transmit the sensor. Specifically, in the example shown, the optical interface 40 is formed by a green light-emitting diode which simultaneously and additionally also signals the presence of a supply voltage, ie "power-on." The use of green light-emitting diodes is advantageous because green light is conducted particularly well by POF light guides.

In the example shown is on the optical interface 40 an adapter 50 plugged or applied, via which a telegram, which sends the green LED recurrently, in a light guide 60 feeds. In this light guide 60 For example, it is a simplex POF fiber optic cable that can be laid independently of the other electrical cables. Here, lengths of up to 50 m are possible.

Communication via the optical interface 40 and the light guide 60 For example, it can be used to indicate synchronization to a transmitter or transmitter of the light curtain. For example, the green LED in the in 1 The receiver unit shown light up brighter when an optical synchronization to the transmitter of the light grid.

In the exemplary embodiment shown, the telegram is transmitted in one direction only and a reception of data by the sensor 10 is not initially planned there. However, this could be delayed in time on the same optical fiber or independently on a second fiber. This would then as a light guide 60 expedient to use a duplex POF optical waveguide.

At the other end is the light guide 60 via a connection piece 62 with a monitoring unit 70 where the telegram is converted into electrical signals and suitably further processed.

The adapter 50 It consists essentially of a transparent plastic part and is made by means of a resilient clamp 80 , which is a bent sheet metal strip, on the housing 20 of the sensor 10 attached. The orientation of the adapter 50 relative to the windscreen 22 of the housing 20 done by catch marks on the adapter 50 , With the help of these locking marks, the adapter 50 Centered center and also can be ensured that viewed in the longitudinal direction Einkoppelstelle 51 of the adapter 50 directly above the optical interface 40 of the sensor 10 to come to rest. The optical interface 40 For example, it can be formed by an opening in a rating plate in which a transmitting light-emitting diode is arranged.

The coupling point 51 is protected by a seal, not shown here against ingress of dirt and moisture.

The defined positioning of the adapter 50 relative to the housing 20 also serve a front stop element 54 and lateral stop elements 52 ,

In the adapter 50 , which can also be referred to as fiber coupler and viewed, is from the front 24 A commercially available Simplex POF optical fiber inserted and with a knurled screw 58 secured against pulling out.

A special quarter-circle-shaped light-guiding element 59 , which directly to the adapter 50 injected, deflects the emitted light of the LED by 90 ° in the optical waveguide. The two fiber ends of the light guide 60 are cut as sharply as possible to avoid unwanted reflections. The maximum permissible attenuation of the optical fiber used should be less than 150 dB / km, otherwise the range is reduced too much.

The spring clip 80 for vibration-proof fixing of the adapter 50 can be from both the right and the left side of the case 20 on the case 20 and / or on the adapter 50 be deferred. At its top, the adapter 50 a contour 56 on, which with a corresponding shape of the resilient clip 80 corresponds.

The adapter 50 closes on the spring clip 80 opposite side flush with the side wall of the housing 20 and in particular there is not over. The construction shown in the figures is accordingly characterized in that the adapter 50 essentially only on one side of the housing 20 in the example shown at the top, over the housing 20 protrudes. In any case, remains in conjunction with the mounted bracket 80 free the opposite side surface.

A particular advantage of the variant shown in the figures is that the adapter 50 without the functionality of the sensor 10 incidentally, to influence the optical interface formed by the "power-on" LED 40 can be put on. This can be done in particular optionally or subsequently. It is also very advantageous for the user that no further connector pins are needed and the electrical interface 30 maintains its previous functionality without restriction.

It is also advantageous that the optical interface 40 can be cleaned without problems with water.

Basically, the optical interface and the light guide 60 depending on the protocol used, for secure or even insecure data transmission from and to optical sensors or switching devices.

With the present invention provides a novel sensor, with the help of an existing optical interface and a light guide additional information, for example Diagnostic, status, parameterization and / or configuration data, transmitted to an external monitoring unit or from an external monitoring unit can be routed to the sensor. In the external monitoring unit it can be a computer, a notebook, a programmable logic controller, a special downstream device or basically also to a mobile phone with appropriate additional functions, act. In the external monitoring unit, the data stream unpacked and further processed for further functions. These may be, for example, diagnostic functions or others secure functions, such as Muting or blanking act.

When Main advantages of the invention are especially the high immunity to interference and easy retrofitting.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 29900149 U1 [0007]
• - DE 10046863 [0007]

Claims (19)

Sensor with a housing ( 20 ), in which at least one sensor element for detecting a physical measured variable and a sensor electronics is accommodated and with an electrical interface ( 30 ) on the housing ( 20 ) for connecting the sensor ( 10 ) to a control and evaluation unit and with one on the housing ( 20 ) formed optical interface ( 40 ) characterized in that in the region of the optical interface ( 40 ) on the housing ( 20 ) for operatively connecting the sensor ( 10 ) with one from the sensor ( 10 ) remotely located external monitoring unit ( 70 ) Medium ( 50 ) for connecting at least one light guide ( 60 ) available. Sensor according to claim 1, characterized in that the optical interface ( 40 ) is formed by a light emitting diode or a plurality of light emitting diodes. Sensor according to claim 1 or 2, characterized in that the optical interface ( 40 ) is formed by a light source for an indication of the power supply. Sensor according to claim 1 to 3, characterized in that the optical interface ( 40 ) is set up for bidirectional data exchange. Sensor according to one of claims 1 to 4, characterized in that the optical interface ( 40 ) is set up for full duplex data exchange. Sensor according to one of claims 1 to 5, characterized in that the light guide ( 60 ) comprises a plurality of optical fibers. Sensor according to one of claims 1 to 6, characterized in that for guiding the light at least one circular segment-shaped light-guiding element ( 59 ) is available. Sensor according to claim 7, characterized in that the circular segment-shaped light-guiding element ( 59 ) is a plastic injection molded part. Sensor according to one of claims 1 to 8, characterized in that an adapter ( 50 ) which is releasably attached to the housing ( 20 ) and with the optical interface ( 40 ) can be brought into an optical operative connection. Sensor according to claim 9, characterized in that on the adapter ( 50 ) at least one optical fiber ( 60 ) is firmly connected. Sensor according to claim 9 or 10, characterized in that on the adapter ( 50 ) Medium ( 58 ) for manual release and connection of at least one light guide ( 60 ) available. Sensor according to one of claims 9 to 11, characterized in that the housing ( 20 ) in the area of the optical interface ( 40 ) has a shape with which the adapter ( 50 ) can be brought in at least partially positive engagement. Sensor according to one of claims 9 to 12, characterized in that on the adapter ( 50 ) Stop areas ( 52 . 54 ) for providing a defined positioning relative to the optical interface ( 40 ) are formed. Sensor according to one of claims 9 to 13, characterized in that the adapter ( 50 ) with a springy clip ( 80 ) on the housing ( 20 ) is fixable. Sensor according to one of claims 9 to 14, characterized in that the adapter ( 50 ) a contour side ( 56 ), with which the resilient clip ( 80 ) for fixing the adapter ( 50 ) comes into engagement. Sensor according to claim 15, characterized in that the resilient clip ( 80 ) is a bent sheet metal strip. Sensor according to one of claims 9 to 16, characterized in that on the adapter ( 50 ) and / or on the housing ( 20 ) Sealant for sealing a coupling region are present. Sensor according to one of claims 9 to 17, characterized in that the adapter ( 5 ) in one with the housing ( 20 ) connected state at least in one spatial direction not over the housing ( 20 ) survives. Sensor according to one of claims 9 to 18, characterized in that the adapter ( 50 ) in one with the housing ( 20 ) connected state only in one spatial direction over the housing ( 20 ) survives.