Abstract: A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the DC motor, permitting accurate rotor position at low rotational speeds. It is emphasized that this abstract is provided to comply with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A reference signal generation unit integrates a staircase signal, to produce reference signal VCTA whose waveform has no abrupt changes in level and which shows a current limit value. A PWM reference signal generation unit generates a PWM reference signal. A supply current measurement unit measures a supply current to a coil. A PWM control unit compares reference signal VCTA with the measurement value of the supply current measurement unit in each period of the PWM reference signal, and sets each transistor in a bridge rectification circuit in a conducting state or a nonconducting state according to the comparison result. In this way, the supply current to the coil is controlled to approach the current limit value shown by reference signal VCTA.

Abstract: A motion control system comprises both a stepper motor and a DC motor. The motors are coupled, and may be operated independently or in concert for various scan types. The stepper motor may be used as an encoder for measuring the position of the mechanism.

Abstract: An appliance for personal use such as a toothbrush, an oral irrigator, a shaver, or a kitchen machine, with a driving mechanism constructed as an electric motor and a control stage that supplies energy to the electric motor. When the electric motor is off, the control stage supplies the electric motor with energy adapted in terms of duration and/or amplitude. The electric motor, when off and in its capacity as an electroacoustic transducer, emits at least part of that energy in the form of audible signals.

Abstract: A stepping motor controller is disclosed that is capable of reducing power consumption of a stepping motor. The stepping motor controller includes a storage unit to store object values of a driving current of the stepping motor, an accumulation unit to accumulate an amount of operation of the stepping motor, and a driving current setting unit to read out an object value corresponding to the amount of operation from the storage unit and set the driving current to the object value. Alternatively, the stepping motor controller includes an accumulation unit that calculates a cumulative amount of operation of the stepping motor, and a driving current setting unit that, when the amount of operation is greater than a predetermined value, determines a critical out-of-step current of the stepping motor by changing in increments the value of the driving current of the stepping motor, and sets the critical out-of-step current with a predetermined margin added as an object driving current of the stepping motor.

Abstract: The controller comprises current sensors for detecting motor currents, an inverter containing a current control means for feeding currents to motor windings, a coordinate transformer that transforms the motor currents in a fixed coordinates system into currents in a first rotational coordinates system, and an angle calculator that transforms a command pulse into a command angle. A second rotational coordinates system composed of a dp axis and a qp axis perpendicular to the dp axis is determined from the command angle. A command current on the dp axis is set to be a value corresponding to a motor current amplitude and another command current on the qp axis is set to be zero. The motor current is projected on the dp and qp axes and controlled so as to make the components on the dp and qp axes coincide with the respective command currents on the dp and qp axes.

Abstract: In one embodiment, the invention involves a method for controlling a stepper motor. The method includes creating an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and directing the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile. In another embodiment, the invention is a stepper motor controller that includes a circuit configured to store an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and direct the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile.

Abstract: A drive unit for calibrating an indicator/meter of a vehicle is provided in which a pointer in an indicator for a vehicle can point immediately after an ignition switch is turned ON, and the frequency of seeing motion of the pointer in an initializing operation by a car driver is reduced. A sensing mechanism (8a-3) is provided to sense an open/close operation of a door. Correspondingly to the sensing of the sensing mechanism (8a-3), a drive-start mechanism (8a-4) starts rotation of a stepping motor using a drive mechanism (8a-1) for initialization. The drive mechanism (8a-1) during initialization rotates the stepping motor to move a driven member toward a stopper.

Abstract: An image forming apparatus for forming an image on a recording medium with a recording head, comprising a conveying roller pair for conveying the recording medium, discharging roller pairs for conveying the recording medium in the downstream of the conveying roller pair, and a stepping motor for driving the conveying roller pair and the discharging roller pairs. A peak value of driving current of the stepping motor after a trailing edge of the recording medium passes the conveying roller pair is smaller than a peak value of driving current of the stepping motor before the tailing edge of the recording medium passes the conveying roller pair.

Abstract: A stepper motor is initialized so that the exciting signal is applied to coils with the step shifted by half of one electric cycle from the rebounding step being synchronized with the timing when the stopper piece is brought into contact with a fixed stopper. The rebounding step, in which the rotor of the stepper motor reverses its rotating direction, can be easily detected. If the rebounding step can be detected, the position for initializing can be easily defined in the angle shifting manner as described above.

Abstract: There is provided a small-sized and slim driving device which is easy to manufacture and capable of producing high output. A magnet has a cylindrical shape, and at least the outer peripheral surface of the magnet is circumferentially divided into n sections magnetized so as to have alternately different poles. The magnet can rotate about a rotational axis of the cylindrical shape. A coil is arranged axially of the magnet and parallel thereto. An outer magnetic pole portion is disposed to be magnetized by the coil, and has a plurality of hair comb tooth-shaped portions opposed to the magnet and arranged around the magnet such that an angle corresponding to the circumferential width of each of the hair comb tooth-shaped portions opposed to the magnet about the rotational axis of the hollow cylindrical shape of the magnet is equal to a predetermined angle A.

Abstract: A device for producing and controlling an alternating current with a direct current source in at least one inductive load, in particular for driving a stepper motor, preferably in microsteps. A device for producing and controlling an alternative current with a direct current source in at least one inductive load, in particular for driving a stepper motor, preferably in micro-steps. Such device includes a control loop circuit having an actuator for the control loop containing a complex programmable logic device (CPLD), which is for connecting the control boy to feedback elements. This provides for a flexible adjustment of the current producing and controlling device to the load to be operated, and to the function of the load, without changing the control loop circuit in which the CPLD is implemented. The actuator can be parameterized by use of a (universal) logic description by parameter constants.

Abstract: For self-switching control of a brushless motor (10) powered by means of a predetermined electrical cycle in order to cause the rotor to advance, the control system comprises an indicator device (100) for indicating the mechanical position of the rotor, the device being associated with a detector device (50) forming an incremental coder device (150) for encoding the mechanical position of the rotor. The system also comprises a motor control assembly made up of processor means (20) for processing the signals coding the mechanical position of the rotor connected to regulator means (30) for powering the plurality of stator windings. The device for indicating the mechanical position of the rotor comprises at least one series (101) of indications of the mechanical position of the rotor corresponding to passing through one electrical cycle of the stator, whereby the incremental coder device (150) delivers the processor means with one synchronization signal for each electrical cycle.

Abstract: There is disclosed a measuring system that is for use with an automatic chemical analyzer and accomplishes accurate measurement reproducibility and low cost. The system has a turntable on which plural reaction cells are arranged circumferentially. A light source and a spectroscopic detector are located on opposite sides of the reaction cell in a detection position. The amount of light transmitted through the cell is measured. A motor having an encoder is connected to the turntable. The output signal from the detector corresponding to each reaction cell is accepted in response to the output signal from the encoder.

Abstract: Disclosed is a driving device for a motor such as a stepping motor etc. for controlling an angle and a speed of the motor, wherein the driving device comprises exciting current detectors for detecting exciting currents of motor windings of the motor, an exciting current amplitude computation means for computing an exciting current amplitude value or the square of the exciting current amplitude value from exciting current detection values detected by the exciting current detectors, and a voltage impression unit for impressing voltages at values corresponding to a deviation value of the exciting current amplitude value and the current amplitude command or a deviation value of the square of the exciting current amplitude value and the square of the current amplitude command to the motor windings.

Abstract: A driving apparatus for a stepping motor, especially which, in micro step driving, partly changes a combination of an energization value to each phase of a motor depending upon a rotational direction of the motor and accurately controls a stopping position of a driven object which is driven by the motor.

Abstract: There is provided a small-sized and slim driving device which is easy to manufacture and capable of producing high output. A magnet has a cylindrical shape, and at least the outer peripheral surface of the magnet is circumferentially divided into n sections magnetized so as to have alternately different poles. The magnet can rotate about a rotational axis of the cylindrical shape. A coil is arranged axially of the magnet and parallel thereto. An outer magnetic pole portion is disposed to be magnetized by the coil, and has a plurality of hair comb tooth-shaped portions opposed to the magnet and arranged around the magnet such that an angle corresponding to the circumferential width of each of the hair comb tooth-shaped portions opposed to the magnet about the rotational axis of the hollow cylindrical shape of the magnet is equal to a predetermined angle A.

Abstract: During the actuation of the flap, the drive frequency of the stepper motor is reduced as a function of the requirements for torque delivered by the motor in order to shift the flap. To that end, information is continuously gathered representing the requirements for torque delivered by the motor in order to shift the flap, the drive frequency is reduced, if appropriate, in response to a detected increase in the torque requirements and, when the drive frequency is below a predetermined maximum frequency, the drive frequency is increased, if appropriate, in response to a detected reduction in the torque requirements. In that way, the power of the actuators can be limited while coping with momentary peaks in torque requirements.

Abstract: A motor driving device includes (a) a wide-angle feeding device for feeding power to three-phase coils in a width of 150 degrees in electrical angles and (b) a feeding amount controller for controlling a feeding amount to the coils. During overlapping periods, in which adjacent coils out of the three coils are in the same fed condition, an amount of a first value is fed to the coils and an amount of a second value is fed during the periods other than the overlapping periods. This structure allows the motor to reduce torque ripples, vibrations as well as noises during its operation, and at the same time, the motor can produce a greater output and operate at higher efficiency.

Abstract: A motor failure detecting module and a motor driving circuit with the module are proposed. The driving circuit includes a sensing unit, a comparator, an AND gate, a switch and a failure detecting module. The sensing unit is to measure the current flowing through the motor and generating a detecting voltage. The comparator is used to compare the detecting voltage with a reference voltage and generate a compared signal. The AND gate receives the compared signal and a control signal and generates a motor driving signal to control the switch. The switch controls the coils of the stepping motor. And the failure detecting module is used to detect whether the motor is failure according to the frequency and/or duration of the compared signal.

Abstract: A flexible closed-loop controller capable of being quickly and easily configured for a broad range of applications. The controller contains a set of control elements that may be configured or reconfigured for any specific application. Built-in configuration management automates configuration of the control elements dependent on user commands or operating conditions. The controller is autonomous after initial configuration, although it may be used interactively. This flexible closed-loop controller is suitable for switching power supplies, linear amplifiers, AC inverters, battery chargers, electronic loads, temperature and pressure management, motor or actuator drives, as well as industrial automation, data acquisition, and automatic test equipment. The controller reduces development time and cost, reduces parts count and cost, and improves performance and reliability of real-time closed-loop systems.

Abstract: Methods, devices and circuits for detecting malfunctions in stepper motors. A signal from a driver circuit to a stepper motor that is proportional to the current in the windings of the stepper motor is detected. This signal is then amplified and integrated for ease of comparison. The resulting signal is then compared to a specific entry in a table of values with each entry in the table corresponding to an operating profile of the stepper motor. If the resulting signal does not correspond to the operating profile for which the motor a configured, the stepper motor is jammed. A suitable alarm and a corresponding sequence of actions may then be triggered.

Abstract: A split detent tactile cueing vehicle control system (10) for a vehicle (11) is provided including an active control inceptor system (12). The active system (12) includes a control inceptor (22) having a plurality of positions and a position sensor (42) that generates a control inceptor position signal. The tactile cueing system (10) also includes a plurality of vehicle performance sensors that generate a plurality of vehicle performance signals. A flight controller (20) is electrically coupled to the position sensor (42) and the plurality of vehicle performance sensors, and generates a control inceptor actuation signal by applying a tactile cueing model having a split detent and in response to the position signal and the plurality of vehicle performance signals. A method of performing the same is also provided.

Abstract: A stepping motor driver having current sensors that detect winding current values, an angle detection device that detects a rotational angle of a rotor, a first coordinate transformation device that transforms winding current values in a rotational coordinate system, an angle calculation device that calculates a command angle value. A third coordinate transformation device transforms the command current values in the rotational coordinate system according to the difference between the command angle value and the rotor angle value, a current control device that generates current control signals in the rotational coordinate system based on the differences between the command current values in the rotational coordinate system and the winding current values in the rotational coordinate system.

Abstract: An apparatus for and method of monitoring the operation of a stepper motor used to control the main burner valve of a gas appliance by positioning a linear actuator. The gas appliance has a pilot burner. A thermopile thermally coupled to said pilot burner produces an electrical output which powers the stepper motor and a control microprocessor. The control microprocessor monitors the waveforms of potential induced by rotational motion into the unenergized stator coils of the stepper motor. By analyzing the waveforms, the microprocessor can monitor the start time, stop time, direction of the rotational motion, and maximum length of travel of the linear actuator.

Abstract: To prevent erroneous detection when a step motor is not rotated by a simple constitution. A control circuit controls to make a transistor to ON/OFF in a rotation detection period immediately after finishing a drive pulse in a state in which transistors is made ON. A comparator compares detection voltage produced at a connection point OUT2 between a resistor for detection and a coil with threshold voltage Vss, determines that a step motor is rotated when the detection voltage is equal to or lower than Vss and determines that the step motor is not rotated when the detection voltage is not equal to or lower than Vss. In this case, current ia does not flow immediately after finishing the drive pulse and therefore, the detection voltage produced at the connection point OUT2 becomes voltage having a polarity reverse to that of the threshold voltage Vss and does not become equal to or lower than Vss and therefore, the comparator determines that the step motor is not rotated.

Abstract: An abnormality detector for motor drive system easily detects, using a CPU, abnormality such as short circuit or disconnection in magnetic field coils of a motor, wiring, an open/close element, etc., which are controlled by a microprocessor (CPU). The open/close elements conducting an open/close operation sequentially in response to pulse outputs P1, P2 generated by the CPU, drive the magnetic field coils. Surge voltages generated upon interrupting the mentioned open/close elements are OR connected through a diode, and input to a temporary storage circuit. Then the CPU reads out, stores and resets the surge voltages using pulse edges of the pulse output P1 or P2. When any generation of the surge voltage is not stored in the temporary storage circuit, the CPU operates an abnormality alarm display.

Abstract: In one embodiment, the invention involves a method for controlling a stepper motor. The method includes creating an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and directing the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile. In another embodiment, the invention is a stepper motor controller that includes a circuit configured to store an information set that defines a first acceleration profile of a stepper motor and a first deceleration profile of the stepper motor; and direct the stepper motor to follow either a second acceleration profile or a second deceleration profile after the stepper motor begins to follow either the first acceleration profile or the first deceleration profile.

Abstract: A system for driving a stepper motor and adapting characteristic parameters of the stepper motor comprising a driver sub-system, responsive to control signals, for transferring power to the stepper motor. A power supply provides a driver current to the driver sub-system. A current detection device, responsive to the driver current, generates a digital feedback signal representative of the driver current. A digital processor, responsive to the digital feedback signal, generates the control signals. The digital processor is further responsive to a software algorithm to generate the control signals. These control signals provide functionality comprising detecting forces applied by the stepper motor to a load preventing a stall condition, adapting stepper motor speed and torque parameters, and limiting applied forces and driver current.

Abstract: A stepping motor comprises a permanent magnet type rotor with a plurality of poles secured to a rotating shaft and a stator having stator magnetic poles with stator magnetic pole teeth in which excitation windings are wound on a plurality of magnetic poles in a star or delta connection, wherein the rotor is magnetized in different directions alternately circumferentially to satisfy the following equation: M=4F/3 where M is the number of poles of the rotor and F is the number of the stator magnetic poles, the rotor is cylindrical in shape with the stator rotatably disposed inside, disposed opposing the surfaces of the stator magnetic pole teeth through an air gap which is of a uniform dimension throughout the circumference between the surfaces of the stator magnetic pole teeth of the stator and the rotor, and the surface magnetic flux distribution thereof has a substantially sinusoidal wave form circumferentially.

Abstract: A stepping motor control circuit sets the setting values of each defining a driving pulse period corresponding to a number of velocity steps at the time of accelerating or decelerating a stepping motor in a register, and performs calculation so as to divide each difference between driving pulse periods in between respective setting values into a predetermined number of pieces to change the driving pulse period. By doing so, this smoothly controls the acceleration and deceleration of the stepping motor without enlarging circuit scale and stepping out even if there is no excessive torque margin.

Abstract: A direct current motor rotation control apparatus, a method and device for controlling a rotational speed of a direct current motor, and an apparatus having the direct current motor rotation control apparatus. The apparatus and device control rotational operations of a direct current motor such that the direct current motor rotation control apparatus includes at least one rotation detecting brush which detects a signal indicative of an operation of the direct current motor, a motor driving circuit which drives the direct current motor by applying the direct current drive voltage to the pair of electrode brushes, a reference voltage generating device which generates a reference voltage a comparator which compares a voltage detected by the rotation detecting brush with the reference voltage generated by the reference voltage generating device and produces an output comparison voltage, and a motor control circuit which adjusts the direct current drive voltage based on the output comparison voltage.

Abstract: A method for the acceleration of the adjusting movement in a positioning system in which at least one stepping motor is controlled at a variable control frequency f, the adjusting speed is dependent upon the control frequency f, and a positioning step of the adjusting movement is initiated at every period of the control frequency f.

Abstract: The stepping motor driver comprises an inverter for feeding stepped currents to windings of a stepping motor, a position detector for obtaining a detected angle of a rotor of the stepping motor and a current controller for controlling the inverter. In a d-q rotational coordinate system in which the d-axis is in the direction of the magnetic flux of the rotor and the q-axis is in the direction perpendicular to the d-axis, an excitation angle for a winding is determined from a d-axis component and a q-axis component of a command current to the winding, a lead angle control signal is computed from the excitation angle, and a phase of an applied voltage to the stepping motor is controlled using the lead angle control signal.

Abstract: In an indicating instrument for a vehicle including a step motor and a stopper unit for stopping a pointer at a zero position, a memory for pre-storing a zero-level electric angle as a correction value at which zero-return alternating signal becomes a zero level at least twice after a zero-return signal is supplied. When the phase of the zero-return alternating signal becomes the zero-level electric angle, the zero-return signal is stopped to provide induced voltage induced in the stator of the step motor. If the induced voltage is lower than a threshold voltage, it is judged that the pointer is stopped.

Abstract: An energy absorbing filter for reducing mechanical oscillations in motor is disclosed. The energy absorbing filter places a virtual shunt across the motor windings so as to dissipate mechanical vibrations as resistive losses. This is accomplished by the placing of a large capacitance in parallel with the windings. The impedance of the filter and the windings combined is purely resistive. The motor may be any kind of motor including a 2-, 3-, or 5-phase hybrid step motor. The filter may be realized as an analog or digital filter, or may be a hybrid of the two. Additionally, the filter may be realized through hardware or through software in the form of a computer program.

Abstract: The stepping motor driver comprises an angle computing element that receives rotor position detection signals from an encoder and calculates a detected angle representing the rotational angle of the rotor, and a lead angle controller that generates a corrected command angle based on the difference between a command angle given from outside and the detected angle. The lead angle controller calculates an angle deviation that is the difference between the command angle and the detected angle, compares the angle deviation with a predetermined value, outputs the command angle as the corrected command angle if the angle deviation is less than the predetermined value, and outputs a value obtained by adding an approximated lead angle to the detected angle as the corrected command angle if the angle deviation is greater than, or equal to, the predetermined value, and the phase of voltage applied to the motor is controlled according to the corrected command angle.

Abstract: A rotation detector apparatus and a rotation control apparatus for the DC motor is disclosed wherein rotational operations of a rotor of the DC motor are controlled by detecting at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor. The pulsed output signal from at least one motor rotor rotation detector brush is processed by signal processing circuitry to regulate the at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor.

Abstract: A stall detection method and system for a stepper motor ascertains a stalled condition according to current rise time of the windings. The motor is determined to be in a normal running condition when current rise time of opposed windings is substantially constant, including monotonic increases and monotonic decreases, in cycles of the rotor. The motor is determined to be in a stalled condition when the current rise time of opposed windings has a relative short-long pattern.

Abstract: A DC motor control device and a DC motor control method are configured to calculate driving motion time and DC motor current flow per unit time, or DC motor total current flow and driving motion time, every continuous driving motion of the DC motor, and interpose a drive stopping time to stop the DC motor for a time corresponding to the calculated value every time before a subsequent driving motion starts. Alternatively, they are configured to interpose a drive stopping time to stop the DC motor for a time calculated by cumulating such time corresponding to the calculated value over a plurality of occurrences every time before a subsequent block of driving motions starts after each block of driving motions.

Abstract: A motion control system comprises both a stepper motor and a DC motor. The motors are coupled, and may be operated independently or in concert for various scan types. The stepper motor may be used as an encoder for measuring the position of the mechanism.

Abstract: A method and apparatus for controlling acceleration and velocity of a stepper motor in which a phase offset is selected depending on motor velocity. The optimal phase offset indicates the position of the winding which generates the maximal driving moment. The increase of the driving force and the extension of the range of steady-state movement is achieved for advanced motor coils commutation with constant frequency using velocity feed back and gradual step-wise phase shift where the phase offset is selected depending on rotor velocity. The invention may be effectively applied to servomotors, stepper motors, motors having certain limitations on movement parameters, such as limitations on acceleration and other types of motors.

Abstract: The stepping motor driver comprises current sensors that detect winding current values, an angle detection means that detects a rotational angle of a rotor, a first coordinate transformation means that transforms winding current values into winding current values in a rotational coordinate system, an angle calculation means that calculates a command angle value, a third coordinate transformation means that transforms command current values into command current values in the rotational coordinate system according to the difference between the command angle value and the rotor angle value, a current control means that generates current control signals in the rotational coordinate system based on the differences between the command current values in the rotational coordinate system and the winding current values in the rotational coordinate system, a second coordinate transformation means that transforms the current control signals in the rotational coordinate system into current control signals in a fixed coord

Abstract: Stepped rotary motion is imparted to the rotor of a stepping motor by alternately driving at least first and second coils which interact with a plurality of magnetic poles on the rotor. When each of the coils transitions from a driven to a non-driven state, the continued motion of the rotor causes a back electro-motive force to be generated in the coil. The electro-motive forces produced by the coils are rectified, integrated, and then compared with a threshold to determine if a motor stall condition exists.

Abstract: A method for driving a stepping motor which performs a micro step driving of the present invention makes a rise through rate variable by matching a step difference related to a change in a value of current when a value of current caused to flow in the stepping motor is increased, and makes a fall through rate variable by matching a step difference related to a change in a value of current when the value of current caused to flow in the stepping motor is decreased. Particularly, at a point of the change of increase/decrease of the value of current caused to flow in the stepping motor, the rise through rate and the fall through rate matched with the step difference related to the change in the value of current are set, and when the value of current let flow in the stepping motor became a constant value, the rise through rate and the fall through rate are made small.

Abstract: A method and system for controlling a stepper motor that may be used in a paper feed rolling arrangement of a printer. The method includes storing step mode selection data in combination with time data in a single table for retrieval and use by a controller.

Abstract: In a stepping motor control method using an encoder, a timer means is provided, and an excessive advance of a phase during low rotation is restricted to attain a high speed without compromising stability during low rotation by driving the motor in such a manner that a pre-reversal state is recovered a predetermined time after a voltage reversal and a post-reversal state is recovered after one cycle of an angle detecting means. A device is provided which controls a speed by a pulse generator generating pulses at predetermined intervals, which detects a sudden drop in speed from a predetermined time elapsed from the last pulse, and which detects, when a speed is to be recovered, an abnormal drop in motor rotation independent of the motor rotation speed by changing a threshold value of an elapsed time according to an actual speed, a speed command value and an acceleration command value.

Abstract: A method and apparatus for automatically detecting an occlusion or drive system failure in a medication infusion system is provided. The electrical current to an infusion pump is measured and compared against a baseline average current. If the current exceeds a threshold amount, an alarm is triggered. Alternatively, pump motor encoder pulses are measured during a pump cycle. If the number of pulses do not correspond within a normal range, an alarm is triggered. After any alarm is triggered, the pump motor is driven in reverse for an incremental distance in order to relieve the fluid pressure in the system.

Abstract: An electrical motor comprises a stator 1 and a rotor 2, the stator 1 having poles 3 facing circumferential surfaces of the rotor 2 so that the stator 1 forms a magnetic circuit with the rotor 2. The stator 1 further has stator windings 5 grouped into two or more phase windings A, B, which phase windings are separately energisable to induce stator magnetic fields which interact with magnetic fields associated with the rotor 2. A voltage across a stator phase winding is detected by voltage detecting means.

Abstract: A stepper motor control circuit reduces ripple current by applying both fast and slow current decays to a motor phase when current is being reduced in the motor phase while following a falling current waveform. The control circuit uses an initial fast decay to reduce a winding current and then switches to a slow decay until a winding current is sampled again. The control circuitry samples a winding current and compares the sampled current to a reference current to determine if current is to be applied or reduced using fast and/or slow decay methods. Different phase current sample circuits allow either constant current sensing or selective current sensing.