DE102020112985A1 - IO-Link adapter - Google Patents

Abstract

The invention relates to an IO-Link adapter (1) for a communication system in automation and process technology, which comprises an IO-Link master (3) and an IO-Link device (5), with voltage and / or current signals are exchanged, the IO-Link device (5) is suitable for providing and receiving digital data according to the IO-Link standard and for communication between the adapter (1) and the IO-Link master ( 3) a current of at least 50 mA is required, with a first connection (2) on the master side for connection to the IO-Link master (3) and a second connection (4) on the device side for connection to an IO-Link device (5 ) is provided, with means for current and / or voltage limitation (6) of the communication signals applied to the first connection (2) being present in order to increase the current strength and / or the voltage at the second connection (4) for forwarding the communication signals to the IO- Link device (5) to be limited to values, i.e. e enable the use of the IO-Link device (5) in potentially explosive environments, whereby a current source (8) and current sink (7) are available to amplify the current and / or voltage-limited communication signals applied to the second connection (4) to To increase the current intensity at the first connection (2) for forwarding the communication signals to the IO-Link master (3) to the level of at least 50 mA required for IO-Link communication, with the current source (8) as a push switching stage and the current sink (7) is designed as a pull switching stage and the IO-Link adapter (1) is designed to activate the current source (8) and the current sink (7) only when communication from the IO-Link device (5) in the direction of the IO-Link master (3) and to control it in such a way that the current source (8) is activated in the event of a logical one and the current sink (7) in the event of a logical zero. In addition, a method for Operating an IO-Link device (5) in a r in an explosive environment.

Description

The invention relates to an IO-Link adapter according to claim 1 and a method for its operation according to claim 4.

IO-Link is an interface for serial point-to-point communication between field devices, i.e. Sensors or actuators (hereinafter called IO-Link device) with a master unit (hereinafter called IO-Link master) according to the IEC 61131-9 standard. This standard specifies the technology of a digital point-to-point communication interface for small sensors and actuators - SDCI (commonly known as IO-Link ™). It expands the conventional interfaces of digital inputs and outputs defined in IEC 61131-2 by a point-to-point communication connection and thus enables the transmission of parameters to the IO-Link device and the transmission of diagnostic information from the IO- Link device to the IO-Link master and thus to the automation system. This technology is mainly intended for simple sensors and actuators in production automation that use small and inexpensive microcontrollers.

Sensors for automation technology provided with such an interface are also manufactured and sold by the applicant, among others.

Since the current on the signal line marked C / Q must be 50 mA according to the above-mentioned standard, these devices are per se not suitable for operation in an explosive atmosphere due to the danger of ignition they pose.

In order to enable operation in such an environment, the ATEX standards applicable in Europe must be met, whereby the avoidance of high-energy sparks must be assumed, which in view of a logic level of 24-30 volts requires a current limitation. In such an intrinsically safe circuit, the voltage and current must be selected in such a way that ignition cannot take place in the event of a device failure because the ignition energy is less than the minimum ignition energy in the explosive atmosphere.

The ATEX standard requires a barrier that limits the current and voltage (= power). The lower the power, the simpler the design of the electronics in the sensor becomes.

The DE 10 2006 009 827 B4 describes an electronic device suitable for use in a potentially explosive atmosphere with the properties mentioned above.

For the reasons mentioned, what such devices cannot achieve is the generation of IO-Link signals with a current of 50 mA, as this would also have to be made available via the power supply.

On the other hand, there are certainly field devices with low energy requirements that would in principle be suitable for use in potentially explosive environments, but without an IO-Link interface being able to be used.

The object of the invention is to remedy this disadvantage and to use a conventional IO-Link device, i. to enable a field device with IO-Link interface in a potentially explosive atmosphere and to connect it communicatively to a conventional IO-Link master.

This object is achieved according to the invention with an IO-Link adapter having the features of claim 1 and a method having the features of claim 4. Advantageous embodiments of the invention are specified in the subclaims.

The idea of the invention consists in providing an adapter in the communication line between an IO-Link device and an IO-Link master, which on the one hand communicates with the IO-Link master on the required 50 mA signal line and on the other hand with the IO-Link -Device communicates with reduced energy in accordance with the ATEX standards. It is essential that the adapter can be integrated into an existing communication line between IO-Link device and IO-Link master and that no changes have to be made to the device or the master, so that conventional devices can be used.

This creates the possibility of using IO-Link devices in potentially explosive environments. However, the prerequisite is that, on the one hand, the current consumption of the IO-Link device is below the limit value required for intrinsic safety (there is no fixed limit for the supply of the sensor) and, on the other hand, that energy-reduced IO-Link signals from the IO-Link device can be evaluated.

According to a preferred embodiment, the bidirectional signal flow to the IO-Link device is limited by a Zener barrier consisting of a Zener diode, a fuse and a resistor.

So that a "normal" IO-Link master can receive and process the weakened send signals of the IO-Link device, since the IO-Link As described in the standard stipulates a level of at least 50 mA, the communication signals from the IO-Link device are amplified by two controlled current sources, with one current source acting as a current sink. The current source is designed as a push switching stage and the current sink as a pull switching stage and both are only activated when there is communication from the IO-Link device to the IO-Link master, which is checked by a measuring and logic unit . Otherwise they are blocked. Finally, they are controlled in such a way that the current source is activated for amplification in the event of a logic one and the current sink in the event of a logic zero.

Thus, the data traffic with the IO-Link master takes place according to the IO-Link standard with 50 mA and to the IO-Link device with a clearly limited signal current of, for example, 4 mA.

In an advantageous embodiment, a bidirectional repeater is used so that the communication direction and also the current direction can easily be determined by software from the signals sent by the IO-Link master or the IO-Link device, so that the measurements mentioned are superfluous. The IO-Link adapter according to the invention thus functions as a master for the field device and the master for the device.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawings.

• 1 einen diskret aufgebauten erfindungsgemäßen IO-Link Adapter,
• 2 einen erfindungsgemäßen IO-Link-Adapter mit zwei Schaltverstärkern,
• 3 eine bevorzugte Ausgestaltung mit einem Repeater 10 und
• 4 einen Logik-Ablaufplan zum Betrieb einer erfindungsgemäßen Anordnung.

They show schematically:

• 1 a discreetly constructed IO-Link adapter according to the invention,
• 2 an IO-Link adapter according to the invention with two switching amplifiers,
• 3 a preferred embodiment with a repeater 10 and
• 4th a logic flow chart for operating an arrangement according to the invention.

In the following description of the preferred embodiments, the same reference symbols designate the same or comparable components.

The 1 shows the essential components of an IO-Link adapter according to the invention 1 for a communication system for automation and process technology that has an IO-Link master 3 and an IO-Link device 5 as a block diagram. Under an IO-Link device 5 is to be understood as a field device, ie a sensor or an actuator, which is suitable for generating an IO-Link signal. A first connection is on the master side 2 for connection to the IO-Link master 3 and a second connection on the device side 4th for connection to an IO-Link device 5 intended.

In the signal line C / Q are with reference numerals 6th designated means for current and voltage limitation in the form of a resistor R _L and a Zener diode shown - also referred to as a Zener barrier -, with which the communication signals from the IO-Link master 3 towards the IO-Link device 5 be limited to a current of 4 mA. This creates an essential prerequisite for use in a potentially explosive environment.

The resistance R _L is typically 3 KΩ. To improve the signal edges, it can be bridged by an RC network having at least one capacitor and optionally another resistor.

In addition, there are two current sources connected to the signal line C / Q 7th and 8th shown by a logic unit 9 be controlled, more precisely the current source with reference numerals 7th acts as a current sink.

The logic unit 9 is designed to recognize the voltage and current direction on the signal line C / Q and the current sources 7th and 8th to control in an appropriate manner. Is the IO-Link master 3 both power sources become active 7th and 8th high resistance. Is the IO-Link device 5 active, the current source suitable for signal amplification is activated, with an additional current to ground or the supply potential being impressed on the signal line C / Q. By “suitable” it is meant that the power source 8th in the case of a logical one and the current sink 7th activated in case of a logical zero. What is decisive, however, is that the current source and current sink 7th , 8th according to the invention are only active when there is communication in the direction of the IO-Link master 3 he follows.

The 2 shows a further embodiment with two anti-parallel switching amplifiers in a schematic representation. It goes without saying that the switching amplifiers cannot simply be connected in the manner shown. Measures known to those skilled in the art for decoupling, neutralization and current limitation are to be provided here. It is expressly pointed out that the upper switching amplifier in view of the current limitation mentioned as a current source 7th or 8th is to be understood in the sense of the invention. It should have a current gain of 10-12 times that of the IO-Link master 3 Convert unreadable 4 mA signals into 50 mA signals that conform to standards. The lower amplifier should have a gain factor well below 1

The 3 shows a preferred embodiment with a principle from the DE 10 2016 217 706 A1 known data-transparent intermediate unit, here as a repeater 10 is designated. The repeater 10 comprises two function blocks that emulate an IO-Link master or an IO-Link device. Both function blocks are connected to a microcontroller µC. As a result, the IO-Link adapter according to the invention functions 1 compared to the actual IO-Link device 5 as master and the actual IO-Link master 3 opposite as a device. This design is advantageous because the repeater designed as a transceiver 10 both the monitoring of the activities of the IO-Link master 3 or the IO-Link device 5 as well as the determination of the current direction moved to the software area, so that the measurements mentioned above can be omitted. The basic mode of operation, however, corresponds to the aforementioned embodiments.

The 4th shows the method according to the invention as an example in a program flow chart. First it is checked whether the IO-Link master 3 is active. If so, the current sources or switching stages are used 7th and 8th switched to high resistance. If not, it is checked whether the IO-Link device 5 is active. If so, the direction of the current is determined, a check being made as to whether the current is flowing to ground, i.e. whether its push stage is active. If so, so will the push stage 8th in the IO-Link adapter 1 activated to amplify the transmit current. If not, it is checked whether the current flows to the supply potential, and if so, the pull stage 7th in the IO-Link adapter 1 activated. If no current direction is determined, there may be a communication gap in which the push-pull output stages naturally also remain high-resistance.

List of reference symbols

1

IO-Link adapter

2

First connection of the IO-Link adapter 1

3

IO-Link master

4th

Second connection of the IO-Link adapter 1

5

Field device with an IO-Link slave (IO-Link device)

6

Means for (current and voltage limitation (limiting resistor R _L , Z-diode)

7th

current sink (or pull switching stage) connected to signal line C / Q

8th

power source connected to signal line C / Q (or push switching stage)

9

Logic unit for controlling the current sink and source 7th and 8th

10

Repeater for standard-compliant and explosion-proof bidirectional communication

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102006009827 B4 [0007]
• DE 102016217706 A1 [0027]

Claims (4)

IO-Link adapter (1) for a communication system in automation and process technology, which comprises an IO-Link master (3) and an IO-Link device (5), with voltage and / or current signals being exchanged via a connecting line the IO-Link device (5) is suitable for providing and receiving digital data according to the IO-Link standard and a current intensity for communication between the adapter (1) and the IO-Link master (3) of at least 50 mA is required, with a first connection (2) on the master side for connection to the IO-Link master (3) and a second connection (4) on the device side for connection to an IO-Link device (5) being provided, whereby means for current and / or voltage limitation (6) of the communication signals applied to the first connection (2) are present in order to increase the current strength and / or the voltage at the second connection (4) for forwarding the communication signals to the IO-Link device ( 5) to be limited to values that enable the IO-Link device (5) to be used in an explosive environment, whereby a current source (8) and current sink (7) are provided to amplify the current and / or voltage-limited communication signals applied to the second connection (4) in order to increase the current intensity at the first connection (2) for forwarding the communication signals to the IO-Link Increase master (3) to the level of at least 50 mA required for IO-Link communication, wherein the current source (8) is designed as a push switching stage and the current sink (7) is designed as a pull switching stage and wherein the IO-Link adapter (1) is designed to activate the power source (8) and the current sink (7) only when communication from the IO-Link device (5) to the IO-Link master ( 3) and to control it in such a way that the current source (8) is activated in the event of a logical one and the current sink (7) in the event of a logical zero. IO-Link adapter Claim 1 , wherein the means for current and / or voltage limitation (6) is designed in the form of a Zener barrier. IO-Link adapter Claim 1 or 2 whereby it has a bidirectional repeater (10) which is suitable for communicating with the IO-Link master (3) in accordance with the standards and with the IO-Link device (5) with reduced current and voltage values. Method for operating an IO-Link device (5) in a potentially explosive environment, whereby the IO-Link device (5) is communicatively connected to an IO-Link master (3) and between IO-Link device (5) and IO-Link master (3) an IO-Link adapter (1) according to one of the preceding claims is arranged, wherein - it is checked whether the IO-Link master (3) is active, and if so, the current source (8) and current sink (7) are blocked, - It is checked whether the IO-Link device (5) is active and, if so, the current direction is determined and the current source (8) in the case of a logical one and the current sink (7) in the case of a logical zero to amplify the signal current is activated.

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