This circuit has proven useful when interfacing my computer to home made robotics. It is easy to build and use and it can control two DC motors of any current or voltage rating, depending on the rating of the relays. The circuit also provides two shaft encoders for positional feedback to the computer.
Showing posts with label controller. Show all posts
Showing posts with label controller. Show all posts
Sunday, October 26, 2014
74LS192 Computer controller 4 DC motors
Thursday, October 2, 2014
Simplest DC Motor Speed Controller Circuit Diagram
The effect can be eliminated by means of Ri compensation, which essentially entails measuring the motor’s current consumption, relating this to the motor’s instantaneous drop i across Ri, and increasing the supply voltage accordingly.
The load current is measured as the drop across sensing resistor R3. For optimum results, this impedance must be kept about equal to that of the motor. Figure 2 shows the practical circuit of the motor driver based on a power operational amplifier.
Simple DC operated motors with a permanent magnetic stator behave as an independently energized motor. The speed of an ideal motor with an, infinitely low internal resistance is in direct proportion to the voltage applied, irrespective of the torque.
The motor thus runs at a speed at which its reverse electromotive force (e.m.f.) equals the supply voltage.
The reverse e.m.f. is directly proportional to the force of the (constant) magnetic field, and the motor speed.
In theory, therefore, the motor speed can be held constant with a constant supply voltage. The speed reduction observed in practice arises from the voltage drop across the internal resistance, Ri, of the armature winding. Thus, when the motor is loaded, its current consumption, and hence Vai, increases, reducing the effective supply voltage.
The Type Ll65 £rom SGS can supply up to 3 A at a maximum supply voltage of 36 and is therefore eminently suitable for the present applications. cation. Capacitors C1 and Cz suppress noise on the reverse e.m.f. from the motor.
The basic set-up of the supply required here is shown in Fig. l.
In· fact, this calls for a voltage source with a negative output impedance, since it caters for a higher output voltage when the . load is increased.
Due care should be taken, however, in so l extending the circuit, because this readily leads to instability. The motor itself already forms a fairly complex load, since the revolving rotor winding is mainly inductive, and the rotor itself represents a fairly large capacitance.
Simplest DC Motor Speed Controller Circuit Diagram
The load current is measured as the drop across sensing resistor R3. For optimum results, this impedance must be kept about equal to that of the motor. Figure 2 shows the practical circuit of the motor driver based on a power operational amplifier.
Simple DC operated motors with a permanent magnetic stator behave as an independently energized motor. The speed of an ideal motor with an, infinitely low internal resistance is in direct proportion to the voltage applied, irrespective of the torque.
The motor thus runs at a speed at which its reverse electromotive force (e.m.f.) equals the supply voltage.
The reverse e.m.f. is directly proportional to the force of the (constant) magnetic field, and the motor speed.
In theory, therefore, the motor speed can be held constant with a constant supply voltage. The speed reduction observed in practice arises from the voltage drop across the internal resistance, Ri, of the armature winding. Thus, when the motor is loaded, its current consumption, and hence Vai, increases, reducing the effective supply voltage.
The Type Ll65 £rom SGS can supply up to 3 A at a maximum supply voltage of 36 and is therefore eminently suitable for the present applications. cation. Capacitors C1 and Cz suppress noise on the reverse e.m.f. from the motor.
The basic set-up of the supply required here is shown in Fig. l.
In· fact, this calls for a voltage source with a negative output impedance, since it caters for a higher output voltage when the . load is increased.
Due care should be taken, however, in so l extending the circuit, because this readily leads to instability. The motor itself already forms a fairly complex load, since the revolving rotor winding is mainly inductive, and the rotor itself represents a fairly large capacitance.
Simplest DC Motor Speed Controller Circuit Diagram
Saturday, September 13, 2014
Pump Controller For Solar Hot Water System
This schema optimises the operation of a solar hot water system. When the water in the solar collector is hotter than the storage tank, the pump runs. The schema comprises two LM335Z temperature sensors, a comparator and Mosfet. Sensor 1 connects to the solar collector panel while Sensor 2 connects to the hot water panel. Each sensor includes a trimpot to allow adjustment of the output level. In practice, VR1 and VR2 are adjusted so that both Sensor 1 and Sensor 2 have the same output voltage when they are at the same temperature. The Sensor outputs are monitored using comparator IC1.
When Sensor 1 produces a higher voltage than Sensor 2, which means that sensor 1 is at a higher temperature, pin 1 of IC1 goes high and drives the gate of Mosfet Q1. This in turn drives the pump motor. IC1 includes hysteresis so that the output does not oscillate when both sensors are producing a similar voltage. Hysteresis comprises the 1MO feedback resistor between output pin 1 and non-inverting input pin 3 and the input 1kO resistor. This provides a nominal 12mV hysteresis so that voltage at Sensor 1 or Sensor 2 must differ by 12mV for changes in the comparator output to occur.
Pump Controller For Solar Hot Water System
Since the outputs of Sensor 1 and Sensor 2 change by about 10mV/°C, we could say that there is a degree of hysteresis in the comparator. Note that IC1 is a dual comparator with the second unit unused. Its inputs are tied to ground and pin 2 of IC1 respectively. This sets the pin 7 output high. Since the output is an open collector, it will be at a high impedance. Mosfet Q1 is rated at 60A and 60V and is suitable for driving inductive loads due to its avalanche suppression capability. This clamps any inductively induced voltages exceeding the voltage rating of the Mosfet.
The sensors are adjusted initially with both measuring the same temperature. This can be done at room temperature; adjust the trimpots so that the voltage between ground and the positive terminal reads the same for both sensors. If you wish, the sensors can be set to 10mV/°C change with the output referred to the Kelvin scale which is 273K at 0°C. So at 25°C, the sensor output should be set to (273 + 25 = 298) x 10mV or 2.98V.
Note:
The sensors will produce incorrect outputs if their leads are exposed to moisture and they should be protected with some neutral cure silicone sealant. The sensors can be mounted by clamping them directly to the outside surface of the solar collector and on an uninsulated section of the storage tank. The thermostat housing is usually a good position on the storage tank.
Saturday, September 6, 2014
Controller of Solar charger Wiring diagram Schematic
This is the simple Controller of Solar charger Circuit Diagram .When connecting a solar panel to a rechargeable battery, it is usually necessary to use a charge controller schema to prevent the battery from overcharging. Charge control can be performed with a number of different schema types. Lower power solar systems can use a series analog charge controller. Series regulators control the charging current by interrupting the flow of current from the solar panel to the battery when the battery reaches a preset full voltage. MPPT controllers use an inductor for energy storage and a high frequency switching schema to transfer the energy to the battery.
This schema is for a shunt-mode charge controller. In a shunt-mode schema, the solar panel is permanently connected to the battery via a series diode. When the solar panel charges the battery up to the desired full voltage, the shunt schema connects a resistive load across the battery to absorb the excess power from the solar panel. The main advantage of shunt-mode solar regulation is the lack of a switching transistor in the power path between the solar panel and battery. Switching transistors are non-perfect devices, they waste a percentage of available solar power as heat. Inefficiency in the shunt-mode controller’s switching transistor does not effect charging efficiency, it only turns on when excess power is purposely being wasted.
Solar power is routed from the PV panel through the 1N5818 Schottky diode to the battery. When the battery reaches the full setpoint, the output on the lower half of the TLC2272 dual op-amp turns on. This activates the IRFD110 MOSFET transistor and connects the 68 ohm 3W load resistor to the battery. The load across the battery causes the battery voltage to drop, and the comparator schema turns back off. This oscillation continues while solar power is available. The 300nF capacitor across the op-amp slows the oscillation frequency down to a few hertz. The two 100K resistors in series provide a regulated 4.5V reference point for use as comparator reference points.
The 2N3906 transistor is wired with a zener diode in its base schema, when the PV voltage is above 12V, the 2N3906 transistor turns on and enables the comparator schema. The upper half of the TLC2272 op-amp inverts the dump load control signal, this is used to power the high intensity red LED. The LED turns on when the battery reaches the full setpoint. The LED does not waste any useful charging power since it only turns on when the battery is full.
The 78L09 IC provides 9V regulated power to the comparator schemary. Operational power for this schema is provided entirely from the PV panel, there is virtually no power taken from the battery at night.
This schema can be modified for higher amperage by replacing the 1N5818 diode, 68 ohm load resistor and IRFD110 MOSFET with higher power components. If the load resistor is connected directly across the PV panel at noon on a sunny day, the PV output voltage should drop to 12V or less. Higher power PV panels will require a resistor with lower ohms and a higher wattage rating. In cold climates, it may be useful to use the load resistor’s heat to keep the battery warm.
This schema is for a shunt-mode charge controller. In a shunt-mode schema, the solar panel is permanently connected to the battery via a series diode. When the solar panel charges the battery up to the desired full voltage, the shunt schema connects a resistive load across the battery to absorb the excess power from the solar panel. The main advantage of shunt-mode solar regulation is the lack of a switching transistor in the power path between the solar panel and battery. Switching transistors are non-perfect devices, they waste a percentage of available solar power as heat. Inefficiency in the shunt-mode controller’s switching transistor does not effect charging efficiency, it only turns on when excess power is purposely being wasted.
Controller of Solar charger Circuit Diagram
Solar power is routed from the PV panel through the 1N5818 Schottky diode to the battery. When the battery reaches the full setpoint, the output on the lower half of the TLC2272 dual op-amp turns on. This activates the IRFD110 MOSFET transistor and connects the 68 ohm 3W load resistor to the battery. The load across the battery causes the battery voltage to drop, and the comparator schema turns back off. This oscillation continues while solar power is available. The 300nF capacitor across the op-amp slows the oscillation frequency down to a few hertz. The two 100K resistors in series provide a regulated 4.5V reference point for use as comparator reference points.
The 2N3906 transistor is wired with a zener diode in its base schema, when the PV voltage is above 12V, the 2N3906 transistor turns on and enables the comparator schema. The upper half of the TLC2272 op-amp inverts the dump load control signal, this is used to power the high intensity red LED. The LED turns on when the battery reaches the full setpoint. The LED does not waste any useful charging power since it only turns on when the battery is full.
The 78L09 IC provides 9V regulated power to the comparator schemary. Operational power for this schema is provided entirely from the PV panel, there is virtually no power taken from the battery at night.
This schema can be modified for higher amperage by replacing the 1N5818 diode, 68 ohm load resistor and IRFD110 MOSFET with higher power components. If the load resistor is connected directly across the PV panel at noon on a sunny day, the PV output voltage should drop to 12V or less. Higher power PV panels will require a resistor with lower ohms and a higher wattage rating. In cold climates, it may be useful to use the load resistor’s heat to keep the battery warm.
Operation of a high power version of this schema with a wind generator should be possible, although the author has not tried this. For a 20 amp version of this schema, the IRFD110 MOSFET should be replaced with an IRFZ44N and the 1N5818 schottky diode should be replaced with a 20L15T. Both of these parts should have large heat sinks. The 68 ohm/3W resistor should be changed to a much larger resistor, An 0.6 ohm/250W resistor would be able to handle 20 amps at 12V.
