DE20115862U1 - Control device for a motor starter - Google Patents

Description

The invention relates to a control device for a motor starter of an electric motor that can be networked via a bus system, furthermore to a correspondingly designed motor starter and a method for controlling a motor starter for an electric motor that is networked with a bus system.

Modern machines and systems are becoming increasingly automated. They therefore have an ever-growing number of devices with input/output functions. Sensors and actuators provide additional and detailed information about incoming commands, output signals and switching states.

Motor starters are used to start, stop or reverse the electric motors of a machine or system when required - automatically or manually - and to monitor the temperature of the electric motor during operation in order to prevent the motor from overheating and at the same time to monitor the power consumption in order to ensure protection against unforeseen blocking of the motor. In addition to pure motor control, the motor starter also performs motor protection tasks.

With connection technology using conventional wiring, each individual contact of a device is wired conventionally, i.e. in parallel, to the interface modules on site at each machine or to the control cabinet. The result is a larger number of screw terminals, input/output cards and cable harnesses. This increases the costs for planning, design and wiring.

Networking the individual devices via a bus system helps to reduce these costs. This greatly reduces the amount of wiring, reduces the amount of project planning required by pre-wired modules and simplifies commissioning thanks to a smaller number of screw terminals and convenient addressing via the bus software. An example of such a bus system is the so-called AS-Interface bus system, or ASI bus system for short, which is designed for binary sensors (normally closed, normally open and auxiliary contacts) and actuators (relays, contactors, lamps) at the lowest field level.

Motor starters with a control device that can be connected to such a bus system, in particular an ASI bus system, are already being used successfully. However, the disadvantage of the motor starters known to date that can be networked with an ASI bus system is that they are each individually tailored to a specific application, which results in a high variety of variants, which leads to planning difficulties and high production and storage costs. So far, different control devices have been provided for motor starters designed as direct starters, i.e. motor starters that can only initiate an on/off function on the electric motor, and control devices for motor starters designed as reversing starters, i.e. for motor starters that can also change the direction of rotation in addition to the on/off function for the electric motor. In addition, different variants of motor starters or motor starters are required for different sizes of electric motors, which consequently differ in their power consumption.

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Appropriate control devices are required for these motor starters to ensure monitoring of the power consumption as blocking protection, resulting in a very large variety of different motor starters and control devices for this purpose.
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The invention therefore has the task of proposing a control device that can be used as universally as possible for a motor starter of an electric motor that can be networked via a bus system, in particular an ASI bus system, which is designed as an open system and can be individually configured by the respective user for the respective use on direct or reversing starters and can be adapted to different sizes of electric motors with the resulting different power consumption, so that the number of different control devices for such motor starters can be drastically reduced.

To solve this problem, the invention proposes a control device for a motor starter of an electric motor that can be networked via a bus system, which, in addition to at least one evaluation unit for an external temperature sensor, for example a thermistor or thermoclick contact for monitoring the temperature of the electric motor and a current transformer block for measuring the power consumption of the electric motor, also has switching elements by means of which different logical switching states can be specified and which further comprises programmable control electronics that are connected to the at least one evaluation unit for the external temperature sensor, the current transformer block and the switching elements and can be connected to the bus system via an interface and has a data memory. According to the invention, the control electronics are programmed in such a way that a periodic determination of the respective measured values obtained from the external temperature sensors via the evaluation unit and generated by the current transformer block takes place, the switching state specified by the switching elements is queried, a

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a limit value stored in a table is read out depending on the queried switching state of the switching elements and compared with the measured value of the current transformer block and the measured value of at least one evaluation unit for the external temperature sensor is compared with a predefinable limit value, data received from the bus system via the interface is queried and evaluated depending on the switching state of the switching elements and a corresponding control command is generated for the motor starter and finally the motor starter is controlled according to the control command or opened if a limit value is exceeded for the at least one evaluation unit of an external temperature sensor or the current transformer.

According to the invention, the proposed control device makes it possible to configure and parameterize different motor starters by means of the different logical switching states of the switching elements.

This makes it possible to adapt the control device for the motor starter to different electric motor sizes with different power ratings by reading different limit values stored in a table from the data memory depending on the specified switching state of the switching elements and then comparing them with the measured value of the current transformer block. In this way, for example, a motor protection range of 0.18 to 2.2 kW or higher can be set without any problems with a single control device for a motor starter by specifying a corresponding switching state of the switching elements.

In a preferred embodiment of the invention, the control electronics can also be used to adapt to different designs of the motor starters that can be controlled by the control device, depending on the switching state of the switching elements. Thus, depending on the switching state read from the switching elements, the

Control electronics can generate control commands for a motor starter designed as a direct starter or a reversing starter. This suitability of the control device according to the invention for both a direct starter and a reversing starter can also be achieved by simply specifying a corresponding switching position of the switching elements, which is read out accordingly by the control electronics.

The control device can further be programmed to include a reversing starter interlock such that while one power contactor of the motor starter is being activated, activation of another power contactor of the motor starter can be prevented.

The switching elements which serve the control device according to the invention for configuration to a direct or reversing starter or parameterization to different power ranges of electric motors to be switched and monitored can be designed, for example, as DIP switches, jumpers, rotary switches and/or software switches which can be controlled directly via the bus system using a software command, so that the greatest possible flexibility is guaranteed.

The switching elements can further comprise a manual switch, by means of which the motor starter can be controlled with priority over the data received from the bus system, for example in order to form a reversing starter with a manual reversing function via the manual switch. It is also possible to use such a manual switch to reverse the direction of rotation of the electric motor connected to the motor starter provided with the control device according to the invention by carrying out a phase swap using a manual switch, which will be explained in more detail below. A permanent phase swap can also be carried out by setting DIP switches as part of the switching elements accordingly, so that a default setting of the direction of rotation of the motor connected to the

The speed of the electric motor connected to the motor starter can be specified.
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According to an advantageous embodiment of the invention, the control electronics can have inputs that can be connected to external switches such as light barriers or limit switches, and depending on the switching state of the switching elements, the motor starter can be opened when a switching signal from the external switch is present at an input. This embodiment provides a motor starter equipped with a control device designed in this way with two additional external inputs, via which light barriers and limit switches, for example, can be connected. In an operating mode that can be configured using the switching elements, for example, the inputs can each be permanently linked to a direction of rotation for the electric motor, whereby the motor starter is opened immediately when a corresponding switching signal is present from the connected external switch, for example in order to immediately switch off the electric motor in a dangerous situation or as a quick stop for positioning tasks. If the motor starter is switched manually using the manual switch with priority over the bus system, the drive is interrupted in the corresponding manually selected direction of rotation, even if the operator continues to control the direction of rotation manually. In this way, for example, motor starters used on a conveyor line using the control device according to the invention can be designed in such a way that goods being transported on the conveyor line cannot be automatically or manually conveyed into a danger zone controlled by light barriers or limit switches. If the motor starter equipped with the control device according to the invention is operated in automatic mode, i.e. it receives its control commands via the bus system, the external switches connected to the inputs can cause the electric motor to be switched off quickly, since in this case the control electronics acting on the motor starter immediately open the motor starter and there is no need to wait for the corresponding control command via the bus system, which would only arrive with a certain delay due to the longer signal path. In addition to increasing safety, this shortened switch-off time can also be used for positioning tasks in which goods being conveyed on a

must come to a stop at a precisely defined point on a conveyor track or the like that is monitored by switches connected to the inputs. In this way, the safety and benefit of the application of a motor starter designed with the control device according to the invention is significantly increased.

The control electronics can further comprise a device for simulating the heating or cooling of the motor based on the queried temperature measurement values, which is stored in the data memory in the form of an E-function, for example, so that the temperature monitoring of the connected electric motor is further improved.

In addition, the control electronics can be programmed in such a way that they send corresponding feedback data to the bus system in order to enable automated control of a motor connected to the motor starter designed in this way. This feedback data can, for example, be confirmation messages for commands that have been sent from the bus system to the control device and that have been converted by the control electronics into a corresponding control command for the electric motor by evaluating the measurement data and the switching position of the switching elements. Warning messages and error messages can also be sent to the bus system as feedback data.

The control device according to the invention can further comprise display elements for displaying the measured values and/or the generated control commands for the motor starter in order to enable the operating personnel to easily check the function.

The switching elements of the control device designed according to the invention can also indicate further features of the motor starter, which are implemented accordingly by the control electronics of the control device. The control electronics can be programmed in such a way that in

Depending on the switching state of the switching elements, the motor starter can be controlled to form a gentle brake for the electric motor or, when a control command is generated to open the motor switch, a signal can be generated to control a self- or externally powered brake for the electric motor.

The method underlying the control device according to the invention for controlling the motor starter for the electric motor, which is networked with a bus system, in particular an ASI bus system, is based on the fact that temperature and power consumption measurement data are continuously monitored and compared with limit values and, in addition, the data from the bus system is evaluated, whereby control commands for controlling the motor starter are generated depending on the evaluated data and the monitored measured values. In order to create the greatest possible flexibility, the invention proposes that different configurations and parameters are specified via switching elements and evaluated together with the data from the bus system and the measured values, so that motor starters designed as direct or reversing starters can be controlled and electric motors with different power consumption can be monitored.

Further details of the invention are explained in more detail below with reference to the schematic drawings. They show:

Figure 1 shows a schematic block diagram of the inventive

appropriate control device for a motor starter,

Figures 2a and 2b as a composite figure a schematized

Flowchart of the software programmed in the control electronics of the control device according to the invention,

Figure 3 shows a schematic representation of the use of the inventive

Control device on a motor starter designed as a direct starter,

Figure 4 shows a schematic representation of the use of the control device according to the invention on a motor starter designed as a reversing starter.
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Figure 5 is a flow chart of a control device according to the invention
quick stops in automatic mode

Figure 6 is a flow chart of a control unit according to the invention.

direction of locked manual operation of a

Motor starter

Figure 1 shows a schematic of the structure of a control device for a motor starter 1. The motor starter 1 is used to switch an electric motor (not shown here) on or off as required, whereby, depending on the design of the motor starter 1, the direction of rotation can also be changed and, in addition, the electric motor is monitored during operation with regard to its operating temperature and power consumption to protect it from damage.

As can be seen in further detail from the illustrations in Figure 3 and Figure 4, the motor starter is inserted into a motor power line 3, which is usually three-phase, and is able to switch on an electric motor M as required with the aid of at least one contactor 16 in the case of a direct starter according to Figure 3 or with two contactors 16.1, 16.2 in the case of a reversing starter according to Figure 4, by closing the contactors 16 or 16.1 or 16.2 and thus the motor power line 3 or

is opened to stop the electric motor M. The opening and closing of the contactor 16 or the contactors 16.1 or 16.2 is effected by an electronic control unit 10, which generates corresponding control commands and transmits them to a contactor 16 or 16.1 or 16.2 via a control line 16a.
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When the motor starter is designed as a direct starter according to Figure 3, the only power contactor 16 provided, which is also referred to as the main contactor, switches the motor power line 3 on or off according to the data received via the bus system 2, which are converted into a control command by the control device 10, in order to put the electric motor M into or out of operation accordingly.

In the case of a reversing starter according to Figure 4, the two alternately controllable power contactors 16.1 and 16.2 enable the electric motor M to be switched on and off and its direction of rotation to be changed. The power contactor 16.1 switches the motor power line 3 to the electric motor M in a similar way to the embodiment according to Figure 3 in order to start it running in one direction of rotation. However, if the power contactor 16.1 is open, the electric motor M can be connected to the motor power line 3 via the branch marked with reference number 3a by closing the power contactor 16.2, whereby the connections of the branch 3a are switched in such a way that the phases of the motor power line 3 are swapped and the electric motor M can therefore be operated in the opposite direction. In addition, the power contactors 16.1 or 16.2 in the embodiment according to Figure 4 or the only power contactor 16 in the embodiment according to Figure 3 also switch a further contact which enables the actuation of a motor brake 4 when the electric motor M is switched off.

To operate the power contactors 16 or 16.1 and 16.2, the control electronics 10 communicates via a line 14a with an ASI interface 14, which, via a connecting line 14b, in a manner known per se,

Establishes communication with a bus system 2, here an ASI bus, via which, for example, data representing control commands addressed to the control electronics 10 of the motor starter 1 can be received and corresponding feedback can be given from the control electronics 10 to the ASI bus 2.

In order to prevent illogical control commands, the control device 10 is also programmed in such a way that it includes a reversing starter lock for the reversing starter, in which no control of the other power contactor 16.2 or 16.1 can be effected for the period in which one of the power contactors 16.1 or 16.2 is controlled and the electric motor 11 moves in the corresponding direction of rotation. If a power contactor 16.1 or 16.2 is controlled via the ASI bus, subsequent switch-on commands for the other power contactor arriving via the ASI bus are ignored and not forwarded by the control device 10.

To ensure the motor protection function, the control electronics 10 also have an input for a temperature line 15a, which is supplied by at least one external temperature sensor accommodated in the electric motor M and an associated evaluation unit and enables monitoring of the operating temperature of the electric motor M.

Thermistors or thermoclick contacts, for example, can be considered as external temperature sensors housed in the electric motor M, but of course other designs can also be used to measure and monitor the temperature of the electric motor M.

Furthermore, the control electronics 10 has an input for a line 13a, via which measured values of a current transformer block 13 in the motor current line 3 can be read, by means of which a monitoring of the

Power consumption of the electric motor M connected to the motor power line 3 is possible.

To ensure its operation, the control electronics 10 are supplied with the necessary operating voltage via a supply line 30.

The supply line 30 and the motor power line 3 can be housed in a common plug and can be connected to a power bus system, for example, so that the motor starter 1 can be easily installed. While the motor power line 3 is supplied with a voltage of 400 V, for example, the supply line 30 for the control electronics 10 is supplied with a voltage of 24 V, for example.

The control electronics 10 also have an input for a line 11a, which connects the control electronics 10 to switching elements 11, via which various logical switching states can be specified, which can be read by the control electronics. These switching elements 11 can be, for example, DIP switches, jumpers, manual switches and/or software switches that can be directly controlled via the ASI bus 2.
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Furthermore, a plurality of display elements 12 are connected to the control electronics 10 via a line 12a, by means of which various operating states of the motor starter 1 as well as error messages and the like can be displayed as required.
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The control electronics (10) also communicates with a data memory 18 via a line 18a.

To simplify production, the motor protection electronics used can be essentially taken from the electronics of digital circuit breakers and can, for example, have an 8-bit microcontroller from Fujitsu with the designation MB 89P637. The ASI part consists of

&zgr;. B. from an ASI chip A ² SI from AMI and a standard 8051 microcontroller.

It is essential for the motor starter 1 according to the invention that the control device shown in Figure 1 comprises switching elements 11, by means of which different logical switching states can be specified for the control electronics 10. For example, by using switching elements 11 in the form of DIP switches and/or jumpers, different switching states can be communicated to the control electronics 10, which enable them to control a motor starter with only one contactor 16 according to Figure 3, which is designed as a direct starter, or alternatively to control two contactors 16.1, 16.2 according to Figure 4 alternately in order to control a motor starter 1 designed as a reversing starter with the control device otherwise unchanged.

Furthermore, different current ranges can be set via the switching elements 11 according to the switching position of the DIP switches or jumpers, which the control electronics 10 compares with the measured values supplied by the current transformer block 13, which correspond to the power consumption of the electric motor M. In this way, by simply changing the switching position of the switching elements 11, the control electronics 10 can be adapted to different power sizes of the electric motors M to be connected without any other structural changes.

Table 1 shows, by way of example, various positions of a four-pole DIP switch as switching element 11, which represent different current ranges with which the control electronics 10 can compare the measured values of the current transformer block 13 in order to cause the electric motor M to be switched off by correspondingly controlling the contactor 16 or the contactors 16.1 and 16.2 when a limit value is exceeded.

An additional rotary switch can also allow fine adjustment of the current value between two current ranges.

Table 1:

pole 3 4 Set current range 1 2 O O 0.6A 1 O O O 0.8A O1 O O 1.0A 1 1 1 O 1.2A oO 1 O 1.5A 1 O 1 O 1.7A O1 1 O 1.9A 1 1 O 1 2.1A oO O 1 2.6A 1 O O 1 3.6A O1 O 1 5.0A 1 1

Table 2 also shows configurations for two additional poles of a DIP switch in which the control electronics 10 are set to a direct starter, while Table 3 shows configurations for a reversing starter.

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Table 2 : Table 3:

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pole Jumper Pos. "right" ["OFF"] 7 8 configuration 0 0 1 0 Direct starter 0 1 (only the main contactor is controlled) 1 1

pole Jumper position “left” [“ON”] L3 exchanged 7 8 configuration 0 0 Automatic reversing starter Phases L1, L3 1 0 Automatic reversing starter and phases L1, 0 1 Direct starter with manual reversing function 1 1 Direct starter with manual reversing function and
exchanged

The function "Automatic reversing starter and phases L1, L3 swapped" contained in Table 3 is used to reverse the direction of rotation of the electric motor M by means of a simple configuration of the control electronics 10 if the basic direction of rotation of the electric motor M is incorrect when it is connected to the motor power line 3, e.g. due to mechanical reasons such as gears, installation position, etc. This minimizes the need for complex rewiring in the event of installation errors when commissioning a system.

If the switching elements 11 are also designed with a manual switch, for example a corresponding key switch, the configurations "direct starter with manual reversing function" and "direct starter with manual reversing function and phases L1, L3 swapped" also included in Table 3 can be achieved, wherein the control electronics 10 is preferably programmed in such a way that the switching positions of the manual switch are carried out with priority over all other control commands.

The motor starter 1 can also be provided in a manner known per se with a mechanically acting latching module which, if the power contactor 16.1 or 16.2 is welded due to a short circuit or the like and thus remains in the ON position even without a switch-on command, ensures that the other power contactor cannot be switched on, regardless of the switching commands from the control electronics 10.

In the following, the programming taking place in the control electronics 10 is explained in further detail using the block diagram according to Figures 2a and 2b, which continue one another.

First, the control electronics are initialized at 100 and the main program 101 is called, in which the control electronics 10 waits for new measured values from the current transformer block 13 and from the evaluation units of the external temperature sensors, which are fed to the control electronics 10 via the lines 13a, 15a. The subprograms are also called, which are explained in more detail below.

For example, every 390 //s at 110 a sampling interrupt 111 is called, in which the values of the current transformer block 13 and the evaluation units of the external temperature sensors are read in via the lines 13a and 15a and at 112 the communication with the ASI bus 2 is handled via the ASI interface 14 and the lines 14a, 14b.

by reading the bus data, e.g. for control commands such as "switch on motor", and sending the generated bus feedback data.

At 102, the new measured values from the evaluation units of the external temperature sensors and the current transformer block 13 are saved and processed, and at 103 the switching elements 11 or the logical switching position stored therein are read in and evaluated, for example according to Tables 1 to 3. Depending on the switching position of the switching elements 11 determined at 103, the limit value for the selected setting corresponding to this switching position and stored in a table is read out at 104 from the data memory 18 of the control electronics 10 via line 18a and subjected to an actual/setpoint comparison at 106 in order to determine whether or not the measured values of the current transformer block 13 are below the limit value stored in a table for the selected setting read out in accordance with the switching position of the switching elements 11. This enables the variable power adjustment of the control device with measuring ranges according to Table 1.

Furthermore, a temperature simulation is carried out at 105 in which the control electronics generates a simulation of the heating or cooling of the electric motor M based on the temperature measurement values supplied via the line 15a.

If the heating value of the electric motor M obtained during the temperature simulation is above the limit value stored in the control electronics and/or the measured value for the power consumption of the electric motor M supplied by the current transformer block 13 is above the limit value stored in the table for the selected setting read in at 104, a tripping command is generated at 107 and the power contactor 16 or 16.1 or 16.2 connected to the line 16a is opened in order to switch off the electric motor M and protect it from damage. Otherwise, the motor is controlled in accordance with the control commands received from the bus system 2.

This control of the power contactors 16 or 16.1 or 16.2 and thus also of the display elements 12 takes place in the subprogram which is identified by the reference number 103.

If no triggering is necessary, a release reset is generated at 107 and a return to the main program is made via 108 and a new sampling interrupt is called for reading in the measured values and the bus data.

It is essential here that the control electronics 10, depending on the switching position of the switching elements 11, evaluates both the data provided via the ASI interface 14 from the ASI bus 2, i.e. the concrete commands for controlling the electric motor M, and the measurement data of the current transformer block 13 and/or the external temperature sensors obtained via the evaluation units, depending on the respective logical switching position of the switching elements 11 in order to control the electric motor M.

In this way, it is possible to control a wide variety of motor starters 1 with a single control device, regardless of whether they are designed as direct or reversing starters, and also to control a wide variety of power sizes of electric motors M, since the corresponding limit values are stored in the data memory 18 of the control electronics 10 and are activated by a logical switching position of the switching elements 11.

Within the scope of the invention, it is therefore particularly possible to produce a motor starter 1 designed with the control device, which can be individually expanded and configured.

Thus, in a simple embodiment, the motor starter 1 can have a housing with installation space for two power contactors, but can only be equipped with a single power contactor 16, whereby with appropriate

Position of the switching elements 11, a direct starter according to Figure 3 with an electronically selectable motor protection up to 2.2 kW, for example, can be designed. In addition to controlling the power contactor 16 for switching the electric motor M on and off, a further contact or a signal for actuating a brake 4 for the electric motor M can also be switched.

By installing an additional power contactor in the existing second installation space of the motor starter, a configuration with two power contactors 16.1, 16.2 as shown in Figure 4 is achieved, whereby the control electronics 10 can be easily switched to act as a reversing starter by appropriately positioning the switching elements 11, whereby the motor protection can again be freely selected and adapted to the respective electric motor M. The power contactor 16.1 is used to switch on the electric motor M in a first direction of rotation, power contactor 16.2 in the opposite direction of rotation.

When the motor starter 1 is designed with two contactors 16.1, 16.2, in addition to being controlled as an automatic reversing starter in conjunction with a hand switch as a further switching element 11, it can also be designed as a direct starter with a reversing contactor that can be operated manually via the hand switch or it can also be designed to generate a phase swap using DIP switches in order to reverse the direction of rotation of the electric motor M, even if it has already been connected to the motor power line 3.

Of course, it can also be provided to change the assignment of the power contactors 16.1 and 16.2 to generated control commands via a specific switching position of the switching elements 11, so that a change in the running direction logic of the electric motor M is also possible without rewiring.

A further logical switching position of individual switching elements 11 can also generate the formation of a soft brake for the electric motor M. In this case, the three phases of the motor power line 3 are switched via both power contactors 16.1 and 16.2, for example two phases via power switch 16.1 and the third phase via power contactor 16.2. When the electric motor M is switched off, the control electronics 10 configured via this switching position of the switching elements 11 first controls the switching off of the power contactor 16.2 and only after a time delay that can be selected if necessary also the switching off of the power contactor 16.1, so that the electric motor M still carries out a certain after-run - the soft brake - when switched off.

All of the aforementioned configurations can be indicated, i.e. configured, by a correspondingly assigned logical switching position of the switching elements 11, whereby the motor protection can also be adapted to the size of the connected electric motor M within wide limits by selecting the corresponding limit values, i.e. can be parameterized accordingly.

Further configuration options for the control device for the motor starter 1 according to Figure 1, which is equipped with the control electronics 10, result from the fact that the control electronics 10 has additional inputs 17, here for example two such inputs 17, to which external switches (not shown in detail), for example light barriers or limit switches, can be connected. These switches can be arranged on a conveyor line, for example, and monitor danger areas into which goods to be conveyed must not be conveyed, with the conveyor device being driven via the motor starter 1 and an electric motor M connected to it.

Via these inputs 17, the control electronics 10 is initially able to transmit the switching pulses emitted by the switches via the ASI interface 14 to

the ASI bus 2 in order to signal a corresponding switching state, for example the entry of a conveyed item into a monitored danger zone on the ASI bus 2, so that a corresponding stop signal can be sent to the control electronics 10 via the ASI bus 2 and a PLC or the like connected to it. In addition, however, the control electronics 10 is able, through appropriate configuration using the switching elements 11, to automatically and immediately open the motor starter 1 when a corresponding measurement signal is present at the inputs 17, without having to wait for the corresponding control command from the ASI bus 2. This results in a clear time advantage and the fastest possible reaction to the corresponding switching signal of the switch connected to input 17, since the PLC connected to the ASI bus 2 can only send a corresponding switch-off signal with a delay, since processing cycles and the longer signal path must still be taken into account here.

Figure 5 shows a schematic flow chart over time which shows such an opening of the motor starter 1, initiated directly by the control electronics 10, to produce a quick stop in automatic mode. From top to bottom, one can first see the circuit diagram D1 of the switch connected to input 17, in the diagram D2 below it the delayed switch-off command which is sent to the control electronics 10 via the ASI bus 2, and in the bottom diagram D3 the accelerated opening of the motor starter due to the direct triggering by the control electronics 10. The switch-off command which arrives with a time delay via the ASI bus 2 serves only as a reset command to enable the motor starter 1 to be switched on again in automatic mode.

In this way, reaction times of e.g. a maximum of 30 ms can be achieved until the motor starter 1 opens, which represents a significant reduction compared to bus control.

If the motor starter 1 is operated manually via a hand switch in the manner already explained above, the control electronics 10 can also open the motor starter 1 immediately if a corresponding signal is present at one of the inputs 17 and prevent further operation in this direction of rotation.

Figure 6 shows a corresponding flow chart for such a locked manual operation of the motor starter 1. The topmost of the three diagrams D4 arranged one above the other shows the signal edge of the switch connected to input 17, the middle diagram D5 shows the position of the manual switch and the bottom diagram D6 shows the motor current switched by the motor starter 1 to the electric motor M.

It can be seen that after the rising signal edge of the switch connected to input 17 (diagram D4), it is no longer possible to operate the motor in the selected direction of rotation manually, although if the motor starter 1 is designed as a reversing starter, it is of course possible to operate in the opposite direction of rotation. When operating in the opposite direction of rotation, the blocked direction of rotation can only be switched manually again after the falling edge of the switch connected to input 17 (diagram D5) has been detected.

This so-called locked manual operation described above can be freely configured, for example, with one of the switching elements 11 designed as DIP switches for the corresponding control of the control electronics 10.

For example, it is also possible to adapt the switching characteristics of the switches connected to inputs 17, for example with regard to

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Signal output due to missing signal current or generated signal current from the switch.

In this way, the greatest possible flexibility is achieved with a single motor starter with the corresponding control device, so that the large number of different motor starters in various designs as direct or reversing starters and with different motor protection areas can be dispensed with. It is only necessary to insert a short-circuit fuse in the motor power line 3 upstream of the motor starter or a group of such motor starters, but this can be done in a known manner.

In particular, a modular design of a motor starter with an individually adaptable and expandable control device is possible, whereby starting from a simple direct starter, additional functions can be easily added by installing an additional power contactor and, if necessary, a manual switch, and the motor protection functions can be quickly and easily adapted to changed performance data of the connected electric motor by changing the switching position of the switching elements.

Claims (14)

1. Control device for a motor starter ( 1 ) of an electric motor (M) that can be networked via a bus system ( 2 ), comprising at least one evaluation unit for an external temperature sensor for measuring the temperature of the electric motor (M), a current transformer block ( 13 ) for measuring the power consumption of the electric motor (M), switching elements ( 11 ) by means of which different switching states can be specified and programmable control electronics ( 10 ) that are connected to the at least one evaluation unit for an external temperature sensor, the current transformer block ( 13 ) and the switching elements ( 11 ) and can be connected to the bus system ( 2 ) via an interface ( 14 ) and have a data memory ( 18 ), wherein the control electronics ( 10 ) is programmed in such a way that - a periodic determination of the measured values generated by the evaluation units for the external temperature sensors and the current transformer block ( 13 ) is carried out, - the switching state specified by the switching elements ( 11 ) is queried, - a limit value stored in a table is read out from the data memory ( 10 ) depending on the switching state of the switching elements ( 11 ) and compared with the measured value of the current transformer block ( 13 ) and the measured value of the at least one evaluation unit for the external temperature sensor is compared with a predefinable limit value, - data received from the bus system ( 2 ) via the interface ( 14 ) are queried and evaluated depending on the switching state of the switching elements ( 11 ) and a corresponding control command for the motor starter ( 1 ) is generated therefrom, and - the motor starter ( 1 ) is controlled in accordance with the control command or, if a limit value for the at least one evaluation unit for an external temperature sensor or the current transformer block ( 13 ) is exceeded, is opened. 2. Control device according to claim 1, characterized in that control commands for a motor starter ( 1 ) designed as a direct starter or a reversing starter can be generated by means of the control electronics ( 10 ) depending on the switching state of the switching elements ( 11 ). 3. Control device according to claim 2, characterized in that it comprises a reversing starter lock, by means of which activation of a further power contactor of the motor starter can be prevented during activation of a power contactor of the motor starter. 4. Control device according to one of claims 1 to 3, characterized in that the switching elements ( 11 ) are designed as DIP switches, jumpers, rotary switches and/or software switches controllable via the bus system ( 2 ). 5. Control device according to one of claims 1 to 4, characterized in that the switching elements ( 11 ) comprise a manual switch by means of which the motor starter ( 1 ) can be controlled with priority over the data received from the bus system ( 2 ). 6. Control device according to one of claims 1 to 5, characterized in that the control electronics ( 10 ) have inputs ( 17 ) which can be connected to external switches, such as light barriers or limit switches, and depending on the switching state of the switching elements ( 11 ) of the motor starter is opened when a switching signal from the external switch is applied to an input ( 17 ). 7. Control device according to one of claims 1 to 6, characterized in that the control electronics ( 10 ) further comprises a device for simulating the heating or cooling of the electric motor (M) on the basis of the queried measured values of the at least one evaluation unit for an external temperature sensor. 8. Control device according to one of claims 1 to 7, characterized in that the control electronics ( 10 ) are further programmed to output feedback data to the bus system ( 2 ) via the interface ( 14 ). 9. Control device according to one of claims 1 to 8, characterized in that display elements ( 12 ) are provided for displaying the measured values and the generated control commands for the motor starter ( 1 ). 10. Control device according to one of claims 1 to 9, characterized in that the control electronics ( 10 ) are further programmed such that, depending on the switching state of the switching elements ( 11 ), the motor starter ( 1 ) can be controlled to form a soft brake for the electric motor (M). 11. Control device according to one of claims 1 to 10, characterized in that the control electronics ( 10 ) are further programmed such that the running direction of the electric motor (M) is reversible depending on the switching state of the switching elements ( 11 ). 12. Control device according to one of claims 1 to 11, characterized in that the control electronics ( 10 ) are further programmed such that when a control command for opening the motor starter ( 1 ) is generated, a signal for controlling a self-supplied or externally supplied brake ( 4 ) for the electric motor (M) is generated. 13. Motor starter, characterized by an associated control device according to one of the preceding claims. 14. Motor starter according to claim 13, characterized by a housing with two installation spaces for power contactors ( 16.1 , 16.2 ) for the electric motor (M) that can be controlled by the control device, so that a direct or reversing starter can be formed as desired, which can be configured and parameterized by means of the switching elements ( 11 ).