Download Electrical and electronical training

Electrical and electronical training
I.
Basics of electrics
Connection of electrical switches, electrical bulbs, circuit breaker, staircase switches,
contactors. This part will include connection of an AC 3-phase motor with frequency changer.
Fig. 1: Connection of training stand
During interconnection of power electronics an attention has to be taken to three types of
wires PE, N and L. The circuitry in buildings have to be divided at least into two circuits:
lights and electrical sockets – each circuitry has its own circuit breaker.
Sockets are connected according to Fig. 2 with hot wire always on the left.
Fig. 2: Conection of electrical socket and staircase switch
Screw terminal is used to divide the wires (neutral, ground and hot) into several branches. In
screw terminals the yellow pads are used for ground wires.
Special circuitry is for motors (asynchronous or induction motors) or other high power
equipment. Special attention has to be taken with motor label – the most important is
connection type (delta or start) with according voltages and currents, power in kW,
revolutions per minute and power factor. These values are input for frequency changer. The
revolutions are slightly less than calculated from frequency (optimal frequency is usually 50
Hz). For example 50x60=3000 revolutions so the real frequency can be 2850 Hz, or for motor
with division factor 2 or 3 (number of magnetic poles) it can be 1430 Hz or 970 Hz. Optimal
operation is when motor is operated with nominal (50 Hz) frequency. The frequency cannot
drop very low since the cooling air flow cannot efficiently cool the motor (typically no less
than 20 Hz). The frequency from frequency changer is usually between 35 – 65 Hz. There are
other important parameters in frequency changer – for example Ramp (how fast the motor
should start or stop to operate).
Fig. 3: Motor label and motor unit
3-phase connection: star (higher voltage) or delta (lower voltage) on motor – Fig. 4.
Fig. 4. : Connection of delta and star for 3-phase motors
Fig. 5: Frequency changer and graph showing optimal frequency
II.
Basics of electronics
Connection of parallel and in series resistors (Fig. 6) – OR and AND functionality (LED
connection with resistors), connection of potentiometer and buttons. Typical LED (LED is a
diode – longer contact is +) has a voltage drop of 1,8 V, the current which is required through
LED is typically 10 mA – hence from V = R.I (ohm law) a needed resistor can be calculated.
Measurement 1 (parallel and in series connection): 9V battery, 2x LED (identical), 1x
680ohm (Ω) – measure voltages and currents.
Fig. 6: Parallel and in series connection
Multimeter and measurement of voltage, current, resistance, diodes, (capacitors and J, K or
Pt100 thermocouples for better multimeters) – Fig. 7.
Fig. 7: Measurement of voltage and current
Fig. 8: Resistor color code
Fig. 9: Connection of button and voltage divider
Measurement 2 (button and potentiometer as a voltage divider): 9V battery, 2x LED, 1x
680ohm, 1x button, 1x potentiometer (2k5). Fig. 9.
Measurement 3 (photoresistor): same as Measurement 2 but instead of 680 ohm resistor use
photoresistor. Fig. 10.
Measurement 4 (diode): same as Measurement 2 but in series with 680 ohm put diode in both
directions.
Fig. 10: Schematic for photoresistor, diode and capacitor – with electrolytic capacitors a special care has to be
taken about polarity
Capacitors have also something like a color coding of resistors but only using a special codes
for certain values - http://grathio.com/assets/capacitor_tags.pdf (e.g. 103 means
10x103pF=10nF). Basically electrolytic capacitors are cylindrical.
Measurement 5 (tyristor): 9V battery, LED, 680 ohm, 220 ohm, 1k ohm, 2x button, tyristor
(cathode is -, anode is +)
Fig. 11: Description of TIC106 and diagram for tyristor control
Transistor is a device with two PN junctions. Basically there are bipolar junction transistors
(BJT) and Field effect transistors (FET). For NPN transistors the negative connector is called
emittor (or source for FET), the posive connector is called collector (or drain for FET) and the
controlling conector is called base (or gate for FET). It can be used to build various circuits –
for example amplifiers of flip-flops (basis for logic circuits).
Fig. 12: Schematic of transistors
Measurement 6 (basic astable circuit): 2x 3,3 uF, 2x 680 ohm, 2x 820k ohm, 2x 470k ohm, 2x
680k ohm, 2x NPN transistors. R2 and R3 transistors can be varied either only 470k ohm
(higher frequency), or in series 820kohm and 680kohm (lower frequency). The frequency can
be computed using f = k/(0,69C1R3+0,69C2R2) (where k is in our case approx. 2). For
C1=C2 and R2=R3 there are precomputed values of frequencies – Fig. 13, Fig. 14 and Fig.
15.
Assume that transistor, TR1 has just switched “OFF” (cut-off) and its collector voltage is
rising towards Vcc, meanwhile transistor TR2 has just turned “ON”. Plate “A” of capacitor
C1 is also rising towards the +9 volts supply rail of Vcc as it is connected to the collector of
TR1 which is now cut-off. Since TR1 is in cut-off, it conducts no current so there is no volt
drop across load resistor R1.
The other side of capacitor, C1, plate “B”, is connected to the base terminal of transistor TR2
and at 0.6v because transistor TR2 is conducting (saturation). Therefore, capacitor C1 has a
potential difference of +5.4 volts across its plates, (6.0 – 0.6v) from point A to point B.
Since TR2 is fully-on, capacitor C2 starts to charge up through resistor R2 towards Vcc.
When the voltage across capacitor C2 rises to more than 0.6V, it biases transistor TR1 into
conduction and into saturation.
The instant that transistor, TR1 switches “ON”, plate “A” of the capacitor which was
originally at Vcc potential, immediately falls to 0.6 volts. This rapid fall of voltage on plate
“A” causes an equal and instantaneous fall in voltage on plate “B” therefore plate “B” of C1 is
pulled down to -8.4V (a reverse charge) and this negative voltage swing is applied the base of
TR2 turning it hard “OFF”. One unstable state.
Transistor TR2 is driven into cut-off so capacitor C1 now begins to charge in the opposite
direction via resistor R3 which is also connected to the +9 volts supply rail, Vcc. Thus the
base of transistor TR2 is now moving upwards in a positive direction towards Vcc with a time
constant equal to the C1 x R3 combination.
However, it never reaches the value of Vcc because as soon as it gets to 0.6 volts positive,
transistor TR2 turns fully “ON” into saturation. This action starts the whole process over
again but now with capacitor C2 taking the base of transistor TR1 to -8.4v while charging up
via resistor R2 and entering the second unstable state.
Then we can see that the circuit alternates between one unstable state in which transistor TR1
is “OFF” and transistor TR2 is “ON”, and a second unstable in which TR1 is “ON” and TR2
is “OFF” at a rate determined by the RC values. This process will repeat itself over and over
again as long as the supply voltage is present.
The amplitude of the output waveform is approximately the same as the supply voltage, Vcc
with the time period of each switching state determined by the time constant of the RC
networks connected across the base terminals of the transistors. As the transistors are
switching both “ON” and “OFF”, the output at either collector will be a square wave with
slightly rounded corners because of the current which charges the capacitors.
Fig. 13: Connection of astable multivibrator circuit
Fig. 14: Table of frequencies for R and C
Fig. 15: RC discharging circuit with time constant T=RC, at 5T the capacitor is fully discharged
Measurement 7 (transistor as an amplifier): 1kohm, 47kohm, button, NPN transistor, 2x LED
Fig. 16:Circuit of amplifier with transistor
Measurement 8 (operational amplifier non-inverting): 9V battery, 6k8, 2x 480, 220, LM741,
potentiometer
Measurement 9 (operational amplifier inverting): 9V battery, 6k8, 2x 180, 1k5, 2x 12k,
LM741, potentiometer
Fig. 17:Circuit of amplifier with transistor
Fig. 18: Inverting amplifier, non-inverting amplifier and voltage follower
Fig. 19: Connection of DIP 741 transistor, aside from DIP package there is also SMD especially for soldering
Measurement 10 (Pulse width modulation): buzzer, Arduino kit (PWM to pin 3, possibility to
change PWM from 0 to 255).
Fig. 20: PWM example
PWM is very often used for controlling of power going to a specific device.
Functionality of diodes, transistors (NPN – BC547B and PNP – BC556B) as amplifiers,
operational amplifiers (741, AD620) as voltage followers and amplifiers, photoresistors,
tyristors (TIC106M), voltage stabilizer (5V – LM7805, 6V – LM7806), relay.
Measurement 11 (relay with soldering): relay, board, 1k5 (or 2k2), LED, 9V battery
Fig. 21: Connection of relay
Measurement 12 (LM7805 voltage stabilizer): 2x 3.3uF, LM7805, diode 1N4007, 9V battery
Fig. 22: Voltage stabilizer
Voltage stabilizer can be done with a Zener diode (diode operating in a reverse direction
Fig. 23: Zener diode, notice the change in scale for positive and negative voltages
Measurement 13 (phototransistor detection of movement): 2x 1k5 (or 1k2), UV diode,
phototransistor (resistors on +)
Fig. 24: OWON SDS6062V - osciloscope, CEM DT-101 - multimeter, SOLOMON SL-976 – soldering station
Fig. 25: Connection of buzzer with two transistors
Fig. 26: 555 timer IC (integrated circuit) with amplifier
Measurement 14 (timer 555): 9V battery, 1k2 (R1), 12k (R2), 100uF, 150ohm, LED, 10nF,
555, C 100uF or 100nF with inductance – functionality of osciloscope
Measurement 15 (timer 555 - monostable): 9V battery, LED, 10nF, 150ohm
III.
Basics of processor programming
Arduino UNO with connection to PC (temperature sensor TMP36, display 1637, buzzer).
The most common communication interfaces are serial, I2C and SPI. For serial (COM,
UART) communication it is necessary to define several parameters (default> COM number:
COM1, baud rate: 9600, data size: 8, parity: none, handshake: OFF).
Fig. 27: COM port (RS 232)
Measurement 16 (state machine with Arduino and COM communication): Arduino, 2x LED,
2x resistor, PC terminal - Hercules, (possible show of closed loop)
Fig. 28: Simple state machine with serial communication
Fig. 29: Arduino UNO, display (TM1637) and stepper drive (ULN2003)
Fig. 29a: Connection of LM35 thermometer
Fig. 30: Pinout of Arduino Uno and configuration of type UNO and Port number
Measurement 17 (display TM1637): display, Arduino
Measurement 18 (display TM1637 with temperature sensor): display, Arduino, temperature
sensor
#include <TM1637Display.h>
const int CLK = 9; //Set the CLK pin connection to the display
const int DIO = 8; //Set the DIO pin connection to the display
int NumStep = 0; //Variable to interate
TM1637Display display(CLK, DIO); //set up the 4-Digit Display.
void setup()
{
display.setBrightness(0x0a); //set the diplay to maximum brightness
}
void loop()
{
for(NumStep = 0; NumStep < 9999; NumStep++) //Interrate NumStep
{
display.showNumberDec(NumStep); //Display the Variable value;
delay(500); //A half second delay between steps.
}
}
Stepper motor - functionality
Fig. 31: Unipolar and bipolar stepper motor
Fig. 32: Stepping modes (driving only one winding, two windings and half-step)
Measurement 19 (driving stepper motor ULN2003): stepper motor, Arduino
Fig. 33: Connection of stepper motor
IV.
Basics of PLC
Measurement 20 (creating of ETH cable): cable, connectors, crimping pliers
Fig. 34: Connection of standard Ethernet
Tecomat Foxtrot 1004 (8DI (4AI), 6DO http://www.tecomat.com/wpimages/other/DOCS/cze/PRINTS/Cat_Foxtrot-CZdatasheets/Foxtrot-CZ-CP-1004.pdf ) programming using Mosaic. Creating of state machine,
connection to Arduino with temperature sensor and stepper drive). Web server on PLC.
Fig. 35: Tecomat Foxtrot and programming ladder diagram
Fig. 36: Layout for PLC training
Mosaic – PLC programming
After a double click on Mosaic icon a screen with Hardware key required appears. If you have
only one or two modules of Tecomat you do not need a key otherwise you need to buy a
professional licence.
Under File -> New -> New project group create a new Project group under a default Mosaic
directory (c:\MosaicApp\).
Then enter the name of new project – then choose modular system Foxtrot.
Choose program name and select programming language LD (ladder).
Choose program instance name and FreeWheeling.
Under Project manager – HW configuration – double click on CPU type and choose
appropriate.
Under PLC Address: 0 choose appropriate connection to PLC. If you do not have PLC you
can choose Simulated. If you have PLC you can connect it by e.g. Ethernet, choose
appropriate connection and click Connect. Then you can close Project explorer. In the top of
the window two small windows appear: one with 0:Halt and the other one with ms (typically
110ms).
Under Icon IO give aliases to inputs and outputs.
After clicking to a chosen block red and blue squares appear in the ladder diagram. When
clicking on blue it means a parallel connection, when clicking on red it means in series
connection.
After placing the block a dialog appears. Here it is necessary to click on icon with … and then
continue with a tab Global and under VAR_GLOBAL are our inputs and outputs.
When placing a timer it is necessary first to choose General Block and then under
Counter/Timer choose TON with some name. Then as an operand we have to enter T#1000 in
order to have 1000ms delay (an example).
If you want to program PLC just choose Program – Compile.
A message with possible errors appears. If everything is OK there are no errors.
Now you can choose under PLC – Run. You have to confirm to send the code to PLC and
choose e.g. Restart type Cold.
Two small windows in the top of the window change slightly.
It means that the program is running. With right click on a particular variable you can choose
to add the watch and in the bottom of the window under the tab Watch you can see all your
watches. Under I/O Settings you can modify value of a particular variable and immediately
see the result under Watch tab and also in ladder diagram.
To stop debugging you can choose PLC – Halt.
V.
Labview with camera
Possible demonstration of programming Labview environment with camera and image
processing.
Fig. 37: Labview camera programming
VI.
PC Schematic for drawing of electrical connections
Start with File-New-Project(Template)-PCSstart
Fig. 38: Start new Project from template
Give it a name and a customer.
Fig. 39: Routing enabled
Fig. 40: Different types of pages: Diagrams, Panel layout, Lists
Fig. 41: Panel layout
Fig. 42: Defining next available name for a part with question mark, updating Lists with Update the List
Drawings for electronic boards: Eagle (https://cadsoft.io/).
References:
https://www.arduino.cc/en/Main/Software
http://www.tecomat.com/kategorie-311-mosaic-_sw_.html
http://www.pcschematic.com/en/download-menu/automation/download-free-electrical-cadsoftware.htm
http://www.ni.com/download-labview/
https://www.visualstudio.com/en-us/products/visual-studio-express-vs.aspx