JP6305061B2 - Solenoid activation method and apparatus capable of changing settings - Google Patents

Description

This application claims priority to US Provisional Patent Application No. 61 / 406,414, filed Oct. 25, 2010.

  The present invention relates generally to a method and apparatus for driving a solenoid, and more particularly to a device with a connector with a configurable connector for driving a solenoid coil.

  Solenoids are widely used around the world. The solenoid then activates a relay or contactor that applies power to the starter motor of most cars. The solenoid activates the locking mechanism of most keyless door systems. Most automatic valves, whether hydraulic or hydraulic, use a solenoid to activate or steer the valve. Solenoids are found in factories, buildings, cars and homes.

  FIG. 1 depicts a typical solenoid 10 showing the major components. Two lead wires 2 carry current to the solenoid coil 3, which generates a magnetic field. The magnetic circuit of the solenoid 10 includes a metal case 4 and a gap 6. The armature 5 is affected by the magnetic field, and its force tends to move or hold the armature 5 in the direction of the hard stop 8. When the armature 5 contacts the hard stop 8 and remains in that state, the armature 5 is expressed as being sealed. Various features are often added to the armature 5 such as a hole 7 for attaching a mechanism in the armature 5 to complete the mechanical connection to the solenoid mechanism. A return mechanism such as a spring is not shown, but this attempts to return the solenoid 10 to the open position when current is removed from the solenoid 10.

  The solenoid converts the current flow into motion through a force on a moving part called the solenoid armature. The solenoid armature may be connected to a variety of mechanisms, and therefore the movement of the armature in the relay opens and closes electrical contacts, while in a solenoid operated valve, the armature is connected directly to one side of the valve seal. In larger valves, the solenoid operates a smaller so-called pilot valve that utilizes some degree of hydraulic or hydraulic amplification, but the basic operation of the valve is initiated by the action of the solenoid.

  Thus, the solenoid is an important component in a wide variety of mechanisms that perform electrical switching, latching, braking, clamping, valve operation, branching or connection, among others.

  The most common method for activating the solenoid involves applying a constant voltage, which may be AC or DC, to the coil. The voltage causes a current flow in the coil that results in the generation of a magnetic field that applies a force to the solenoid armature and moves the mechanism to which the solenoid is attached. However, as will be described in detail below, there are significant difficulties in driving the solenoid in an energy efficient manner with circuitry that does not create additional problems in itself.

  2-4 are examples of circuits used to drive the solenoid. FIG. 2 shows a typical prior art transistor solenoid drive circuit including a transistor 11 capable of conducting current in response to a signal to the input. The current flows through the solenoid 10. When the current conduction in response to the signal to the input by the transistor 11 is stopped, the flyback diode 14 conducts the current, which causes the inductive component of the solenoid 10 to reduce the voltage seen at the transistor 11. In some cases, the transistor 11 is prevented from being destroyed. When the energy of the solenoid 10 is depleted by the recirculation process, the current stops and the solenoid 10 is deenergized.

  FIG. 3 shows a solenoid driver integrated circuit 12 that reduces the holding current of the solenoid 10 using pulse width modulation (PWM) of the supply voltage, such as commercially available from a number of manufacturers. An object of the solenoid driver 12 is to prevent damage to the solenoid 10 and generally required external components, that is, the driver integrated circuit 12, and to reduce radio waves generated during PWM switching to some extent. The flyback diode 14 and the series connection diode 13 are connected. The solenoid driver integrated circuit 12 is of a fixed configuration and is reconfigured for other purposes such as measuring or generating voltage or current, except for those required for limited manual solenoid drive operations. It is not possible.

  FIG. 4 shows a typical prior art fixed configuration sink output module 17 capable of driving the solenoid 10. As is typical in the prior art, the output module 17 does not supply power to drive the solenoid 10, but instead relies on connecting and disconnecting power supplied by the external device power supply 18. ing. In addition, wiring to the solenoid 10 is made using a terminal block 19 as is normal for the fixed configuration output module 17. Moreover, as is common with the output module 17, a protective flyback diode 14 is installed to reduce the voltage generated by the solenoid 10 during the de-energization process.

  As known to those skilled in the art of solenoid driven mechanism design, providing sufficient force of the solenoid at the desired travel distance and producing excessive energy consumption and heat generation of the solenoid coil. There is a delicate balance between them. The amount of current required to move the solenoid to the closed position is large compared to the current required to keep the solenoid closed (i.e., sealed in the technical terminology). Thus, solenoids that remain sealed for long periods tend to be hot, and tend to consume a greater amount of energy than is simply required to keep the solenoids sealed. A delicate balance for the designer of a solenoid driven mechanism is that the predetermined distance to the closed position can be moved reliably, while at the same time excess power despite constant application of power to the solenoid coil. Is to produce a solenoid that does not consume energy or excessively increase in temperature.

  This fundamental design difficulty of the solenoid is the background of the problem that the present invention seeks to solve, and therefore a more detailed explanation of the causes of this design difficulty is provided to illustrate the advantages of the present invention. Present the description.

  The solenoid converts the current flow to a force on the armature, but the force is not a constant function of the current. When the solenoid is sealed, there is essentially no air gap in the magnetic circuit, so the magnetic flux is relatively high at a given current. However, when the solenoid is fully open, there is a gap in the magnetic circuit, which significantly increases the magnetoresistance of the circuit, which is the ratio of the magnetomotive force (MMF) to the generated magnetic flux. . Thus, at the predetermined current, the force on the armature that is fully open can be significantly lower than when the armature is in the sealed position. Therefore, in order to move the armature with high reliability, it is necessary to supply more current than is necessary when the solenoid is sealed. To make matters worse, the high current requirement to seal the solenoid lasts for less than a second, and the solenoid may remain in a conductive seal indefinitely. Energy is wasted.

  Those skilled in the art have previously understood that for a given solenoid current, as the armature approaches the closed or closed position, the force on the armature increases because the magnetic resistance decreases due to the gap being shortened. Since the force applied to a sealed solenoid armature is very high compared to the force on an open solenoid when the current or voltage is the same, one skilled in the art can initially change the solenoid by changing the current or voltage to the solenoid. It was inferred that the solenoid could be kept sealed by supplying a high force to seal the valve and subsequently reducing the current or voltage. By using such a strategy to change the current or voltage, the heat generation of the solenoid coil can be reduced while supplying the high force necessary to close the solenoid.

  In US Pat. No. 6,099,017 (“Suzuki”), the document teaches that the current to the relay coil can be reduced after the relay is closed by making a current control circuit. Unfortunately, the circuit shown in that document is supplied with current to the relay coil by transistors connected in series, thus generating heat and significantly reducing the possible energy savings. Thus, although the invention of Document 1 somewhat reduces the heat generation of the solenoid, this is due to moving some of the heat generation to the transistor. For example, if the solenoid current disclosed in document 1 is reduced to ½ of the initial draw current, this system will reduce the solenoid energy usage to ¼ of the previous level. Unfortunately, another quarter of the energy is consumed in transistor resistance losses. Furthermore, the document 1 does not mention a measure for dealing with the influence of the inductance of the relay coil while the relay is turned off. It is well understood in the art that large voltage swings are generated by removing power from an inductor using a transistor, which is generally mitigated by inserting a current flow path into the flow. Thus, dangerous increases in circuit voltage must be avoided. Generally, a diode is used that can circulate the current in the relay coil while it is off.

  Some skilled in the art have sought to avoid half the energy savings. They inferred that loss in the transistor can be reduced with known power switching techniques that use pulse width modulation (PWM) of the solenoid voltage to quickly turn the transistor on and off to largely avoid the linear region. This strategy works well in inductive circuits where little current initially flows while the transistor is closed. Fortunately, the solenoid is highly inductive and therefore PWM works well. Unfortunately, however, PWM can easily generate jamming unless special care is taken. For applications in industrial control systems, it is almost impossible to impose restrictions on solenoid users.

  Similarly, an integrated circuit such as a Texas Instruments DRV102 PWM valve / solenoid driver or the like first drives the solenoid at full voltage and thereby full current, and then performs PWM of the power signal to the solenoid. It is intended to produce fixed and special purpose electrical circuits that can reduce current. Unfortunately, the integrated circuit can generate undesired electrical interference as described above. For example, the instruction manual of DRV102 manufactured by Texas Instruments states that “electromagnetic radiation can be generated by the PWM switching voltage and current”. In addition, this note suggests that determining the location of noise reduction components may be “ignoring logic”, that is, difficult to predict and may require repeated empirical tests. ing. Furthermore, such integrated circuits typically require the addition of many external components and are fixed configurations: the connector to which the solenoid is attached can only drive the solenoid. The invention described below provides additional applications and flexibility that cannot be obtained using these prior art devices.

  The prior art has not adequately addressed the important design difficulty in solenoid actuation: how to determine whether the solenoid is sealed. For many reasons, the solenoid cannot reach or stay in the closed or sealed position when applying current. The solenoid will not move and may not be able to move in either direction initially. The solenoid coil may be open or not electrically continuous, thus failing to generate the desired magnetic field. The solenoid coil can be shorted. The solenoid can be subjected to vibration, which provides sufficient force to the solenoid to cause the solenoid to become unsealed. Or an instantaneous loss of current may occur, which temporarily reduces the force holding the solenoid. Or, the current applied to the solenoid coil may be slightly less than that required to keep the solenoid armature in a hermetically sealed condition under all physical variations such as ambient temperature. . The prior art teaches only one solution to such a dilemma regarding the determination of the state of the solenoid, which is to allow the solenoid to close the electrical circuit when the solenoid is sealed. is there. FIG. 5 shows an apparatus according to the prior art for determining whether the state of the solenoid is sealed or open. In this prior art system, the controller 90 issues a command to close the solenoid coil 91. After the solenoid coil 91 is given sufficient time for sealing, the controller 90 senses the state of the auxiliary contact 92 mechanically coupled to the solenoid mechanism. Based on the state of the auxiliary contact 92, the controller 90 can estimate the state of the solenoid 91. However, if the solenoid 10 is not a relay, the solenoid 10 must be mechanically connected to the auxiliary contact 92, and such a connection is problematic and costly. Such a strategy requires the use of a set of contacts for this monitoring process, even when the solenoid is part of a relay. Additional electrical circuitry is required to monitor this additional contact, and the startup sequence must be repeated for a system with reduced holding current. If the solenoid is not part of the relay, a set of contacts must be added to the solenoid mechanism. This requirement is prohibited except for critical solenoid systems.

US Pat. No. 7,262,950

  The present invention provides a method and apparatus with a configurable connector for driving a solenoid coil that can provide a sufficiently high force to move the solenoid from a fully open position to a closed position. This can also reduce energy consumption and heat generation of the solenoid coil when the solenoid is sealed. The present invention reduces energy without continuous loss from series throttling transistors or resistors. The present invention facilitates the detection of open or shorted solenoid coils and can reduce current, thereby deactivating the armature to reduce the resulting coil overheating. The present invention eliminates the requirement to use PWM as a drive method and governs the coil off operation without the need for additional components such as diodes. The present invention simplifies the connection to one or more relays or solenoids without requiring an external power source. The present invention allows the determination of whether a solenoid is sealed without the need for auxiliary electrical contact and uses information on the solenoid that is not sealed to essentially force the force on the solenoid armature. The armature can be instantaneously increased and returned to the closed position before the armature moves significantly.

  The present invention extends the teachings of U.S. Pat. No. 6,922,265, U.S. Pat. No. 7,216,191 and U.S. Pat. No. 7,822,896, and U.S. Patent Application No. 13/069292, published as US Patent Application Publication No. 2001/0231176. Is. In past inventions, for very diverse electrical functions ranging from voltage measurement, voltage generation, current measurement, current generation, generation of various power levels, or control of frequency information such as serial communication data Describes a system with a connector whose configuration can be changed, which may constitute any connector pin of the system.

  A number of industrial control problems have been solved by a single version of the product built using these teachings. Compared to conventional industrial control input / output modules, input / output modules with configurable connectors dramatically reduce the number of additional components required, such as power supplies and terminal blocks. An input / output system with a configurable connector eliminates the need for many different fixed configuration modules because the electrical configuration of its connector pins can be changed.

  In the present invention, the pin configuration of the input / output module can be changed during normal operation, so that if a solenoid is connected between two such pins, the voltage across the solenoid can be Can be changed without using any other components or without the use of PWM. Because the present invention allows the pin configuration to be changed from one power supply to another, or the voltage level of any of the plurality of power supplies can be changed, the present invention provides high efficiency. The power supply can be used. Thus, throttling or PWM is no longer required to reduce the voltage across the solenoid, but the use of PWM in the present invention is not excluded if it is determined to be beneficial for some reason. . In addition, the present invention also provides two ways to manage inductive current when off. First, a configurable connectorized module can gradually throttle current while keeping the coil voltage within an acceptable level. Second, by reconfiguring the first pin of the two pins of the solenoid to the same voltage as the second pin, both sides of the solenoid coil are connected to the high and low voltage sides of the same power source. obtain. These two methods address the effects of inductance during circuit off and do not require additional elements to provide safe operation of the circuit.

  Moreover, the present invention provides a connection to the connector pins of other sensing and source circuit elements so that it can be determined whether the solenoid is sealed. The determination is based on the solenoid's electrical inductance being inversely related to the electrical reluctance and the reluctance decreasing as the solenoid air gap approaches zero. The determination is accomplished by applying a periodic or step change in the voltage across the solenoid and measuring the resulting periodic or step change in current. The resulting current is a function of solenoid inductance. Or alternatively, the determination may be accomplished by applying a step or periodic change to the current through the solenoid and measuring the resulting voltage change, but the preferred embodiment is the former determination. Is the method. The determination includes whether the solenoid is sealed, opening, or open. Moreover, in the event that the solenoid is unintentionally lost, the method and apparatus of the present invention increases the solenoid current essentially simultaneously to reseal the solenoid, thereby preventing the solenoid from unintentionally opening. can do. The reseal can be performed without the need for any additional equipment other than that found in the present invention.

FIG. 1 depicts a typical solenoid showing the major components. FIG. 2 is a typical circuit arrangement according to the prior art for driving a solenoid coil, showing the flyback diode that is particularly necessary. FIG. 3 is a typical circuit arrangement according to the prior art using pulse width modulation (PWM) for driving a solenoid coil, showing in particular the necessary series-connected diodes and an additional flyback diode. FIG. 4 shows a prior art circuit that is common in programmable logic controllers or industrial fixed configuration output modules. FIG. 5 shows a prior art device for detecting the unsealed state of a solenoid. FIG. 6 shows an apparatus for changing settings according to the present invention. FIG. 7 shows the connection of a relay or solenoid coil to the module with a connector of the present invention capable of changing settings. FIG. 8A shows the waveform of the command of the present invention when actively suppressing the solenoid current from decaying to zero. FIG. 8B shows the voltage waveform of the present invention when actively suppressing the solenoid current from decaying to zero. FIG. 8C shows the current waveform of the present invention when actively suppressing the solenoid current from decaying to zero. FIG. 9A shows the waveform of the command of the present invention when the solenoid current is attenuated to zero. FIG. 9B shows the voltage waveform of the present invention when the solenoid current is attenuated to zero. FIG. 9C shows the current waveform of the present invention when the solenoid current is attenuated to zero. FIG. 10 shows a model of the resistive and inductive components of the solenoid for purposes of describing the method and apparatus of the present invention for determining the non-sealed state of the solenoid. FIG. 11A shows the voltage waveform of the present invention used to measure the inductance of the solenoid to determine the unsealed state of the solenoid. FIG. 11B shows the current waveform of the present invention used to measure the inductance of the solenoid to determine the non-sealed state of the solenoid. FIG. 11C shows the waveform of the voltage of the present invention used to measure the solenoid inductance to determine the non-sealed state of the solenoid. FIG. 11D shows the current waveform of the present invention used to measure the inductance of the solenoid to determine the non-sealed state of the solenoid. FIG. 12A shows voltage waveforms for an alternative method of the present invention for determining solenoid status. FIG. 12B shows the current waveform for an alternative method of the present invention for determining solenoid status. 2 is an example of an ASIC configured as a pin driver interface device, according to some embodiments of the present invention. 2 is an example of an ASIC configured as a pin driver interface device, according to some embodiments of the present invention.

  FIG. 6 is a functional block diagram of the input / output module 15 with a connector capable of setting change according to the present invention. Within the module 15 of the preferred embodiment, a microprocessor 80 is included, which can direct any of a plurality of signals to one or more pins 16, which are then solenoids or the like. (But not limited to solenoids) of various sensors and actuators. In particular, the input / output module 15 with a connector whose settings can be changed includes one or more power supplies 81, which are similar to those other than the above among a plurality of signals via switching means 82 such as R5 or R6. It may be routed and connected to one or more connector pins 16. When a solenoid is connected between two such pins 16, the configurable input / output module 15 with connector generates one of a plurality of power levels to the solenoid and passes it through the solenoid. Current can be adjusted without the need for PWM.

  The configurable input / output module 15 may include any number of interconnect devices 83. Each interconnect device 83 is connected to one device connector 16 and optionally passes through an internal crosspoint switch to another interconnect device (see FIG. 13 and the associated description). FIG. 6 is extremely stylized and is intended to convey the essence of the module of the present invention.

  FIG. 7 shows the input / output module 15 with a connector according to the present invention in a state where it is connected to the solenoid 10. In this configuration, the module 15 comprises a microprocessor 80 for routing a plurality of power levels from a power supply 81 to pins 1 and 2 of the module 15. Unlike the fixed configuration output module according to the prior art, any of the 15 pins shown in FIG. 7 can be configured for this function. Unlike prior art fixed configuration output modules that require an external device power supply, the present invention does not require an external device power supply and is not shown in FIG. Also, unlike a fixed configuration output module according to the prior art, which requires a flyback diode to protect the output module, the present invention does not require a flyback diode and is not shown. Therefore, the input / output module 15 with a connector of the present invention capable of changing settings can apply one of a plurality of voltages to the connected solenoid 10, thereby realizing the object of the present invention. it can.

  8A, 8B, and 8C show voltage and current waveforms generated as a result of activation of the solenoid 10 using the method and apparatus for suppressing attenuation, and are shown as solenoid drive signals in FIG. 8A. The voltage waveform described below has nine steps. In FIG. 8B, reference numerals 21 to 29 are assigned to the respective stages.

  In step 21, the solenoid voltage is zero, which is the solenoid inactive. The solenoid is not supplied with power and is ready for startup.

  In step 22, the input / output module 15 with the connector whose setting can be changed is connected to the solenoid 10 in response to the solenoid drive signal becoming true. In this preferred embodiment, the startup level voltage is 24V. In response to the applied voltage, the solenoid coil current increases sharply (reference 40) and the solenoid moves quickly because the applied voltage is preferably higher than the sustainable steady state coil voltage. However, by changing the period of step 23, the starting force of the solenoid can be controlled.

  In step 23, the input / output module 15 with a changeable connector maintains the voltage of the solenoid coil at the pull-in level, and the coil current moves asymptotically to a steady state (reference numeral 41). The length of the stage 23 portion is set so that the solenoid current does not reach a steady state in order to control the starting force of the solenoid. At the end of step 41, the solenoid is preferably in the closed or sealed position.

  In step 24, the configurable connectorized input / output module 15 disconnects the activation level voltage from the solenoid and connects the sustain level voltage to the solenoid substantially simultaneously. Alternatively, the voltage level of a single power supply can be varied to achieve the same purpose. The sustain level voltage is selected to provide sufficient holding power to the solenoid, but the sustain level voltage is insufficient to be reliably pulled into the solenoid under any conditions. The sustain level voltage is preferably adjustable by the microprocessor 80. When phase 24 begins, the solenoid coil current 42 begins to decrease in response to the application of a low voltage. The solenoid coil current decreases until a steady state 43 is reached after a period of time, which is a function of the electrical characteristics of the solenoid.

  In step 25, a sustain level voltage is maintained in the solenoid to keep the solenoid sealed. The control system maintains step 25 as necessary. This time can range from milliseconds to months or longer.

  In step 26, the process begins to remove power from the solenoid as the solenoid drive signal begins to become false 31. The inductance of the solenoid (which makes it impossible to quickly reduce the current) makes the pin 16 of the input / output module with a configurable connector much negative with respect to ground, which can damage the switching means 82, Or, because this may destroy it, a configurable solenoid drive circuit can never open its drive transistor to the solenoid. If the solenoid coil comprises a so-called flyback diode, a path is provided for the solenoid current and the energy of the coil is dissipated. However, there is no flyback diode, so the coil voltage goes through zero and becomes negative. Accordingly, the configurable connector / input / output module 15 of the present invention is configured to throttle the coil current and begin to clamp the coil voltage to a value, which in the preferred embodiment is ground. Is approximately −5V.

  In step 27, the throttling process continues until the voltage that the coil can supply drops below the clamped voltage. During phase 27, the solenoid coil current decreases linearly (reference numeral 44).

  In step 28, the reconfigurable connectorized input / output module 15 stops actively throttling the solenoid coil current, and instead provides a fixed transistor gate drive to remove residual energy from the solenoid coil. Dissipate. During step 28, the solenoid current 45 decays exponentially to zero and the solenoid coil returns to the inoperative state.

  At step 29, the solenoid coil is in the same state as it was at step 21: the coil is not activated, the solenoid is not powered and is again ready for activation. The solenoid current 46 is also zero.

  6 and 7, the interface device 84 may be configured to connect one of a plurality of power supplies to the device connector 16 to which the solenoid 10 is connected. For example, the switching means 82 may initially connect a 24 VDC power source to the device connector 16 to achieve a solenoid retraction phase. Similarly, the interface device 84 may subsequently connect a 5 VDC power supply to the device connector 16 to achieve the solenoid's sustained phase.

  9A, 9B and 9C are very similar to FIGS. 8A, 8B and 8C, but connected to the solenoid 10 of the input / output module 15 with a configurable connector rather than throttling the solenoid current. The difference is that the two pins are set to the same voltage on the high voltage side or the low voltage side. In doing so, the solenoid current flows through the module 15 until the solenoid current is depleted. Thus, stage 27 in FIG. 9B remains at 0V and not −5V as in FIG. 8B. The current of FIG. 9C then decreases exponentially to zero at step 46.

  The inductance is in inverse proportion to the magnetic resistance, which is itself a function of the solenoid air gap: the magnetic resistance decreases as the air gap decreases, and decreases completely when the solenoid is completely sealed and the air gap is almost gone. Thus, in the context of the present invention, the determination of whether the solenoid is closed, opening or fully open is accomplished by measuring the inductance of the solenoid coil. The present invention provides a number of methods and apparatus for measuring the inductance. Two methods and two devices are described below and are for illustrative purposes only. Although simpler or more appropriate methods using the features of the present invention are possible, the following description is intended to convey the essence of the present invention.

  FIG. 10 shows a general electrical circuit model used to explain the inductance measurement of the present invention. Specifically, the solenoid 10 is divided into two components. Resistive component 95 is connected in series with inductive component 96. This model facilitates the description of the inductance measurement system.

  FIG. 11A shows the DC voltage across the solenoid. The voltage may be any suitable voltage greater than or equal to 0V. FIG. 11B shows a DC current obtained when the voltage shown in FIG. 11A is applied, and the obtained DC current is 0 or more. FIG. 11C is a sine wave voltage signal of an appropriate frequency applied to the DC voltage signal of FIG. 11A, and the sine wave voltage is sufficiently small that the DC voltage does not affect the operation of the solenoid. On the other hand, it is large enough to generate a measurable current in the solenoid 10. The sine wave voltage signal is established by slightly changing the set value of the voltage of any of the plurality of power supplies 81 connected to the input / output module 15 with a connector of the present invention capable of changing settings. The sinusoidal voltage signal causes fluctuations in the DC current signal of FIG. 11B, which is also essentially sinusoidal. The above variation of the DC current signal is shown in FIG. 11D. The phase of the signal of FIG. 11D relative to the sinusoidal voltage signal of FIG. 11C is a function of the relative magnitude of the two components shown in FIG. 10, the resistive component 95 and the inductive component 96 of the solenoid 10. Specifically, if the resistive element 95 of FIG. 10 is large and the inductive component 96 of FIG. 10 is small, the step of the current signal of FIG. 11D with respect to the voltage signal of FIG. Near to 0 °. However, if the resistive component 95 of FIG. 10 is small and the inductive component 96 of FIG. 10 is large, the step of the current signal of FIG. 11D with respect to the voltage signal of FIG. Close to. Inductive components of the solenoid 10 can be measured using known methods of signal processing that can extract the quadrature component of the current signal.

  Alternative methods and apparatus may be used for inductance measurement, using similar results and possibly simpler and more effective embodiments, such as using periodic square wave excitation instead of periodic sinusoidal excitation. Can do. Furthermore, a step change in voltage or current, and subsequent measurement of current or current response, can provide a similar inductance measurement in embodiments that may be more appropriate for the electrical circuit used.

  An alternative method of determining the solenoid state is by observing the step response rather than the step and magnitude for periodic excitation. FIG. 12A shows the solenoid voltage for a typical energy application and de-energy sequence with a status query pulse used to determine if the solenoid is sealed. The magnitude or polarity and duration of these query pulses are designed to avoid changing the solenoid state. FIG. 12B shows the current for the sequence of FIG. 12A and its query pulses. The three voltages used for energizing, holding, and deenergizing applied across the relay in the method are at the same level in the preferred embodiment, but this is not an important aspect of the invention. The method is described in detail below according to the sequence of events or steps in the illustrated sequence.

  First, the solenoid is deenergized to a zero current and voltage state. In this state, a query pulse of sufficiently small amplitude and duration can be applied to produce a current response 50 without moving the solenoid armature. If the duration of the query pulse is short compared to the L / R time constant of the solenoid in its sealed, unsealed or intermediate state, sampling the response of the current at a known peak, ie at the end of the query pulse Thus, the inductance of the solenoid can be estimated using one sample. As mentioned above, this inductance indicates the state of the solenoid, which is the object of the present invention.

  After some time, energy is applied to the solenoid to generate a current response 51 and a current response 52 or 53 depending on whether the solenoid armature moves. Because the inductance can be measured with respect to the de-energized state, and responses 51 and 53 are both part of a simple true exponential determined by the known inductances described above and known magnetoresistances from other methods. As such, this non-moving pin response can be easily distinguished from the response 51 and 52 pairs that exhibit significantly different curves. This distinction may be made by sampling the current several times along a response where the time separation is short compared to the L / R time constant, so that simple computations by the microprocessor 80 allow simple true From the exponential function, the starting point 52 of the curve can be detected, which indicates the desired movement of the solenoid armature. Since the method does not rely on a double derivative or presence of a vertex that can be relaxed or eliminated if the solenoid armature does not suddenly stop at the end of the energy application process, the tip at the end of the response phase 52 This is an improvement over U.S. Pat. No. 3,946,285, which is a past invention based on this detection.

  If the energy application is successful, the solenoid voltage decreases to a holding level, producing a current response 54 and eventually settles to a low power holding current at the beginning of the current response 55.

  During energy application, a query pulse of any speed appropriate for this application is applied to generate a current response 55. While this is the same as the current response 50, the change in current with stepped amplitude is reduced due to the considerably higher inductance of the sealed solenoid. Here again, as in the case of response 50, a single sample of the peak of response 55 can be used to infer the solenoid's inductance and hence the solenoid's sealed or unsealed state. . Since the inductance in the unsealed state is several times smaller than the inductance in the sealed state, the state of the solenoid can be easily distinguished by the amplitude of the current response 55 with respect to the baseline of the holding current.

  After some time, the solenoid is de-energized, producing a current response 56 and one of responses 57 or 58 depending on whether the solenoid armature moves. These conditions can be distinguished by the same criteria as the criteria for detecting the successful energy application described above, except for detecting the success of deenergization.

  Eventually, a deenergized starting state is reached, and the query pulse produces a current response 59 of any rate appropriate for this application.

  It should be noted that the query pulse indicates the position of the solenoid armature independent of whether armature movement is detected by distinguishing between current curves. For many applications, query pulses alone are sufficient to detect solenoid malfunctions. However, motion detection can indicate success or failure earlier during times when query pulses cannot be applied. Such early detection can be important in applications where activation of other systems immediately follows changes in the state of the solenoid, but only when such changes occur as commanded.

  The above measurement of inductance can always be performed by a system with a connector with a configurable connector according to the invention. Since the measurement does not affect the operation of the solenoid, it is preferable to make this measurement first when the solenoid is energized with a DC voltage greater than zero. The first measurement is used as a baseline for solenoid inductance.

  The above measurement of inductance continues while the command is first issued to seal the solenoid upon activation of the input / output module 15 with the connector with the changeable setting. When the solenoid is in a sealed state, the inductance measured in the sealed state is higher than the measurement of the inductance of the first baseline, which is due to the electrical characteristics of the solenoid as described above. The inductance measured in the sealed state is stored by the microprocessor 80 of the input / output module 15 with the connector whose setting can be changed, and subsequently the solenoid state is sealed or opened using this. Or it is determined whether it is an open state.

  The inductance measurement is performed continuously while the solenoid is to remain closed (while the solenoid voltage is at the lower holding level 25). If for some reason the solenoid becomes unsealed, the inductance will decrease as a result. The inductance measurement detects this decrease in inductance. At substantially the same time, the input / output module 15 with a connector whose setting can be changed raises the voltage of the solenoid to the pull-in value 23 in order to retighten the solenoid 10. In this way, the present invention can prevent the solenoid armature 5 from moving a distance that would affect the mechanical state of the mechanism to which the solenoid 10 is connected. In order to reduce the energy consumed by the solenoid 10 again, after the solenoid 10 is sealed again, the input / output module 15 with a connector whose setting can be changed drops the applied solenoid voltage to the holding voltage 25 again. . Optionally, the method and apparatus of the present invention may increase the solenoid's holding force slightly to compensate for the effects that cause the solenoid to become unsealed by slightly increasing the applied solenoid's voltage.

  8A-8C for determining the damping described above, for the modification described above with reference to FIGS. 9A-9C, and for determining the state of the solenoid described above with reference to FIGS. 10 and 11A-11D. The above method and its modifications may all be implemented in the input / output module with connector and the computer program of the present invention. The computer program may be stored in a memory in the module and executed by a microprocessor in the module. Alternatively, the program may be stored external to the module, for example in a control system, and instructions are sent to the microprocessor in the module to operate the processor. In a further alternative, computer programs for some of the processes of the present invention may be stored in the module's memory, and others may be stored outside the module, for example in memory within the control system. FIG. 7 shows an example of the system controller 85 connected to the module 15. The connection between the system controller and the module may be a standard cable or network connection (eg Ethernet). The connection may be a backplane connector, for example the module may be plugged into a PLC backplane or embedded controller. The connection may be a wireless connection. Without departing from the teachings of the present invention, a configurable input / output module with a connector may: operate as a so-called embedded controller; may be a circuit board that is part of a larger system; or itself May function as a system controller.

  The interface device 84 including the interconnection device 83 as shown in FIG. 6 may be configured as an integrated circuit (IC). The IC is repeated for each device connector 16 within the I / O module 15. Therefore, when there are 25 device connectors 16, 25 ICs are used. Module 15 can include any number of ICs, depending solely on which module includes which number of device connectors 16. In another embodiment, different IC architectures may be used, such as managing multiple device connectors 16 in each IC, or using multiple ICs to manage one or more device connectors. The use of an IC can result in a dramatic reduction in the size and fabrication cost of the module 15 due to the miniaturization afforded by modern semiconductor processes.

  FIG. 13 is a block diagram of an integrated circuit that can implement the interface device 84. Integrated circuit 198 is specifically designed to serve as an interconnect device and may therefore be referred to as an application specific integrated circuit (ASIC). This ASIC is specifically designed to provide the functionality of the interconnect device 83. At some point in the future, such an ASIC can become a standard product from an integrated circuit manufacturer. Thus, the term ASIC as used herein includes standard integrated circuits designed to function as interface devices. Furthermore, the term integrated circuit (IC) as used herein is intended to encompass the following various devices: ASIC, hybrid IC, low temperature co-fired ceramic (LTCC) hybrid IC, multichip module. (MCM) and system in package (SiP) devices. A hybrid IC is a miniaturized electronic circuit that provides the same functionality as a (monolithic) IC. The MCM includes at least two ICs; the interface device of the present invention may be realized by an MCM in which necessary functionality is divided into a plurality of ICs. SiP, also known as chip stack MCM, is a large number of ICs enclosed in a single package or module. In the present invention, SiP can be used similarly to MCM. Theoretically, the interface device of the present invention can be realized using a programmable logic device. However, currently available programmable logic devices, such as field programmable gate arrays (FPGAs), have many functional limitations, such as inability to route power or ground to a given pin, and their use is undesirable. If the FPGA is expanded to overcome these functional limitations, such an improved FPGA may be used as a component for implementing the interface device 84.

  FIG. 13 shows a block diagram of the pin driver ASIC 198. When connected to the microprocessor 80 by a serial communication bus 206 such as an SPI interface, the microprocessor 80 of FIGS. 6 and 7 can instruct the ASIC 198 to perform the circuitry of the interconnect device 83. Although the circuit configuration of FIG. 13 appears to be different from the interconnect device 83, the ASIC can perform the same or similar desired functions. FIG. 6 is a somewhat idealized view intended to convey the essence of the module of the present invention, but FIG. 13 includes more circuit elements where one circuit element is placed inside the ASIC. Nevertheless, FIG. 13 implements all the circuit elements of FIG. For example, FIG. 6 shows a digital / analog converter (D / A or DAC) connectable to the device communication connector 16. In FIG. 13, the digital / analog converter 226 is connected to the output pin 208 via the switch 220. The present invention also includes other circuit arrangements for the ASIC 198 for the same or similar purposes. A person skilled in the art knows how to design such various circuit configurations, and these are intended to be included in the present invention.

  Features of the exemplary ASIC of FIG. 13 will now be briefly described. Power may be applied to pin 208 by closing high current switch 222b and setting supply selector 227 to any available power supply voltage such as 24V, 12V, 5V, ground, or -12V. The available power supply voltage provides the pull-in voltage level and the sustained voltage level necessary to drive the solenoid.

  The ASIC can measure the voltage at pin 208 by closing the low current switch 222 and reading the voltage converted by the analog to digital converter 216.

  The ASIC can measure the current supplied to the pin 208 through a high current switch 222b using a plurality of programmable current limiters 224 that include a current measurement device. The current measurement is used to determine the inductance of the solenoid and whether the solenoid is shorted or open.

  The periodic variation of the voltage to the solenoid used to determine the solenoid inductance can be very easily achieved by slightly changing the voltage of the plurality of power supplies 81, and the appropriate power supply is selected by the supply selector 227. . A step change in the voltage to the solenoid used to determine the solenoid inductance causes the supply selector 227 to change momentarily to increase or decrease the solenoid current to perform the solenoid inductance measurement. This can be accomplished very easily by increasing or decreasing the voltage of the solenoid.

  The ASIC 198 can measure the amount of current flowing to or from the node 208 labeled “Pin” in FIG. The pin driver circuit 198 in this case can use the A / D converter 216 to measure the amount of current flowing to or from the pin node 208, thereby detecting excess current or the Pin node 208. Detects whether the device connected to is functioning or wired correctly.

  The ASIC 198 also monitors the current flowing into or out of the pin node 208 to unilaterally disconnect the circuit 198, thereby protecting the ASIC 198 from damage due to short circuit or other possible damage conditions. The ASIC 198 uses a so-called “overuse detection circuit” 218 to monitor abrupt changes in current that can potentially damage the ASIC 198. The low current switches 220, 221 and 222 and the high current switch 222b disconnect the pin 208 in response to the overuse detection circuit 218.

  The overload detection circuit 218 of the ASIC 198 can establish a current limit with respect to the pin 208, which is set by the microprocessor 80 based on a program. This is what selection 224 requires.

  In order to allow the microprocessor 80 to determine the state of the digital input connected to the pin node, the ASIC can measure the voltage at the pin node 208. As a result, the threshold value of the digital input can be programmed instead of being fixed by hardware. The digital input threshold is set by the microprocessor 80 using the digital / analog converter 226. The output of the digital / analog converter 226 is applied to one side of the latch comparator 225. The other input of latch comparator 225 is routed from pin 208 and represents a digital input. Thus, when the voltage at the digital input at pin 208 passes the threshold set by the digital / analog converter, the microprocessor 80 determines the change in the input, thereby inferring that the digital input has changed state. Can do.

  The ASIC 198 can measure a current signal present at the pin node, which is generated by various industrial control devices. The ASIC 198 can measure signals that vary over the standard 4-20 mA and 0-20 mA ranges. This means of current measurement can be achieved by the microprocessor 80 because the selectable gain voltage buffer 231 generates a convenient voltage, such as 0V, at the output terminal. At the same time, by the microprocessor 80, a selectable source resistor 228 provides resistance to the current path from the industrial control device and its current output. This current enters ASIC 198 via pin 208. Due to the voltage applied to one side of the known resistor, the unknown current from the external device generates a voltage at pin 208, which is measured by analog / digital converter 216 via low current switch 222. The Microprocessor 80 uses Ohm's law to determine the unknown current being generated by the industrial control device.

  The ASIC 198 includes the functions described above associated with the interface device 84. For example, the ASIC 198 can include an interconnect device 83 that includes a digital / analog converter 226, where the microprocessor 80 directs the reception of a digital signal from the microprocessor 80 and directs the signal to the digital / analog converter 226. To convert to an analog signal and to place a copy of this analog signal on pin 208. See Figures 6 and 13.

  The ASIC 198 can also include an interconnect device 83 that includes an analog / digital converter 216, where the microprocessor 80 is programmable to sense an analog signal on any selected contact 16, and analog / digital Converter 216 converts the signal to a digital signal and outputs a copy of this digital signal to microprocessor 80.

  The ASIC 198 can also include a supply selector 227 that places a high current switch 222 b between the selector 227 and the pin 208. The microprocessor 80 can be programmed to operate the supply selector 227 to connect the power supply voltage to the first contact 16 and to connect the return of the power supply to the second contact 16.

  Referring to FIG. 13, there is a 2 × 8 crosspoint switch 210 that serves to connect the sensor to two adjacent pins 208 that are connected to two adjacent device communication connectors 16. A sensor such as a thermocouple can be connected to the precision differential amplifier 212 by the cross point switch 210. The precision differential amplifier 212 is routed through a low current switch 222 and a 2 × 8 crosspoint switch 210 on a 4-way crosspoint I / O 214 followed by an integrated circuit 19 (an integrated circuit for the adjacent contact 16). May be connected to another 4-way crosspoint I / O 214.

  In another refinement of the invention, the module 15 can implement independent control of devices connected to the module 15. For example, if a solenoid is connected to the module 15, the microprocessor 80 may change the voltage of the solenoid slightly and measure the resulting current using a current measurement device in the programmable current limiter 224 to determine the need for inductance. Periodic or continuous measurements can be performed. Further, the microprocessor 80 can perform the steps necessary to shut down the solenoid by throttling or recirculating the current. This allows the module 15 to perform any function necessary to activate the solenoid and check whether the state is sealed or open.

  With reference to FIGS. 6 and 7, the microprocessor 80 generally provides for sensing a particular state of the selected device, such as the inductance of the solenoid, and / or for activating the selected device, such as the solenoid 10, and Configured / programmed by controller 85 to receive instructions from the controller as needed to supply corresponding data to the system controller. Microprocessor 80 may also be programmed / instructed by the controller to apply a particular signal to any one or more selected contacts 16. In addition, the microprocessor 80 is programmed to respond to instructions for transmitting selected types of signals from one or more of the devices to the system controller. In other words, the microprocessor controls the configuration of the interface device 84, and generally the microprocessor is controlled by the system controller. Alternatively, the interface device can be configured in response to messages stored in the memory of the microprocessor 80 of the module 15.

  In some embodiments, the microprocessor 80 has an embedded web server. A personal computer may be connected to module 15 and then to the Internet using an Ethernet cable or a wireless communication device. Here, the personal computer may be a system controller. The embedded web server provides a configuration page for each device connected to the module 15. The user uses a mouse or other keyboard input to configure device functionality and assign input / output pins. The user need only drag and drop icons on the configuration page to determine the specific interconnect device for each of the contacts. In other embodiments, the microprocessor 80 uses a network connection to access a server on the Internet and receives instructions from the server to determine a particular interconnect device for each of the contacts.

  As an example of the operation of the module 15, for example, it recognizes specific input data included in an Ethernet packet including an instruction to activate a specific solenoid connected to the module 15 on a network cable connected to the microprocessor As such, the microprocessor 80 may be programmed.

  The circuit switching device (R1-R12) is shown schematically as an electromechanical relay. In some embodiments, the switching device is implemented with a semiconductor circuit (see FIG. 13 and the associated description). The semiconductor circuit can be realized at a very low cost as compared with the electromechanical relay circuit and can operate quickly. An electromechanical relay is used to illustrate the essence of the present invention.

  For the purpose of illustrating the invention, certain representative embodiments and details have been shown, but various methods and apparatus described herein may be used without departing from the scope of the invention as defined in the appended claims. It will be apparent to those skilled in the art that changes can be made.

Claims (16)

A method of operating the solenoid using an input / output module with a connector capable of setting change electrically connected to a coil of the solenoid,
(A) a step of establishing a start-up current to the coil by connecting a start-up voltage by the module in response to the solenoid drive signal becoming true, the solenoid being closed by the start-up voltage and the start-up current; Or in a sealed state, step;
(B) After the solenoid is in a closed state or a sealed state, a step of changing a continuous voltage and a continuous current of the coil by the module, wherein the continuous voltage or the continuous current is greater than the start voltage or the start current. Small, the solenoid is maintained in a closed or sealed position; and (c) maintaining the sustained voltage and current by the module;
With
Further comprising determining the state of the solenoid by measuring inductance of the coil by the module, wherein the state includes from an open state to a closed state or a sealed state;
In the measurement, when the solenoid driving signal is true and false, the module applies a series of pulses with different amplitudes to the coil, and the module applies the series of pulses with different amplitudes applied. Measuring the step response of the coil when the solenoid drive signal is true and false, and calculating the inductance from the difference in the step response,
The module is
A device communication connector device for connecting at least one conductor between the module and the solenoid;
An interface device for placing any of a plurality of signals on any of the plurality of contacts of the device communication connector device by the module.   The method of claim 1, wherein the step of changing comprises disconnecting the start-up voltage and start-up current from the solenoid and connecting the sustained voltage and current to the solenoid by the module.   The method of claim 1, wherein the changing step includes changing a voltage or current level of a single power supply.   The method of claim 1, wherein the sustained voltage or sustained current is less than 50% of the startup voltage or startup current.   The method of claim 1, further comprising removing power from the solenoid when the solenoid drive signal becomes false.   6. The method of claim 5, further comprising throttling the coil current by the module and clamping the coil voltage.   The method of claim 6, wherein the throttling is continued until a voltage that the coil can supply drops below the clamped voltage.   8. The method of claim 7, further comprising connecting the coil to a fixed transistor drive by the module to dissipate residual energy from the coil after the throttling step. The module is
6. The method of claim 5, wherein a conductive path for dissipating energy from the coil is provided by connecting both sides of the solenoid to a high voltage side and a low voltage side of the same power source.   The method of claim 9, further comprising connecting the coil to a fixed transistor drive by the module to dissipate energy from the coil.   The method of claim 1, wherein the interface device comprises at least one integrated circuit that provides a selectable interconnect device to a particular one of the contacts. The method of claim 11 , wherein the integrated circuit is an ASIC.   The method of claim 1, wherein the interface device includes a microprocessor for placing any of the plurality of signals on any of the plurality of contacts of the device communication connector device by the module. An input / output module with a changeable connector for operating a solenoid,
A device communication connector device for connecting at least one conductor between the module and the solenoid;
An interface device for arranging any one of a plurality of signals at any of the plurality of contacts of the device communication connector device by the module,
The interface device includes a memory for storing a computer program and a processor for executing the program,
The program includes: (a) connecting a starting voltage by the module to establish a starting current to the coil of the solenoid in response to the solenoid driving signal becoming true to the processor, wherein the starting voltage And the solenoid is closed or sealed by a starting current;
(B) After the solenoid is in a closed state or a sealed state, a step of changing a continuous voltage and a continuous current of the coil by the module, wherein the continuous voltage or the continuous current is greater than the start voltage or the start current. Small, the solenoid is maintained in a closed or sealed position; and (c) maintaining the sustained voltage and current by the module;
And execute
The program causes the processor to measure the inductance of the coil by the module to determine the state of the solenoid, where the state includes from an open state to a closed state or a sealed state,
The inductance is measured by applying a series of pulses having different amplitudes to the coil by the module when the solenoid driving signal is true and false, and by applying the series of different amplitudes applied by the module. Measuring a stepped response of the coil when the solenoid drive signal is true and false to a pulse, and calculating the inductance from the difference in the stepped response.
module. A system for operating a solenoid, the system comprising:
An input / output module with a connector capable of setting change, comprising: a device communication connector device for connecting at least one conductor between the module and the solenoid; An input / output module with a configurable connector, comprising: an interface device for placement on any of the plurality of contacts of the device communication connector device;
A controller connected to the module by a communication link, the controller including a memory for storing a computer program and a processor for executing the program, the program providing a solenoid drive signal to the processor. And the signal is sent to the module, which causes the module to:
(A) establishing an activation current to the solenoid coil by connecting an activation voltage, the solenoid being closed or sealed by the activation voltage and coil current; (b) After the solenoid enters a closed state or a sealed state, the continuous voltage and the continuous current of the coil are changed by the module, and the continuous voltage or the continuous current is smaller than the start voltage or the start current, Changing the solenoid so that it is maintained in a closed or sealed position; and (c) maintaining the sustained voltage and current with the module;
And execute
The program causes the processor to measure the inductance of the coil by the module to determine the state of the solenoid, where the state includes from an open state to a closed state or a sealed state,
The inductance is measured by applying a series of pulses having different amplitudes to the coil by the module when the solenoid driving signal is true and false, and by applying the series of different amplitudes applied by the module. Measuring a stepped response of the coil when the solenoid drive signal is true and false to a pulse, and calculating the inductance from the difference in the stepped response.
system. The system of claim 15 , wherein the communication link is an Ethernet link.

Images