In today's video we will learn how to calibrate the A4988 Driver
which are connected to the Ramps 1.4
let's see connections
and how we set it
to function properly when connected to the Arduino Mega
we go with the video
and we will build it step by step
Ramps this Shield 1.4 is regarded as having the best performance for 3D printing
that is why we are using pin to pin connected to a Arduino Mega
A clone can be used without any problems
it is not necessary to use those claiming to be original
They work just to clone
and pin-connected until it matches
perfectly
do not loose because he always Bregue to connect
because it must match all
so I do it with patience and good despacito
step by step
after this well connected and without being on any pin
nor has doubled
we must connect the A4988 Driver
the driver are connected to the potentiometer
this point that this here
to the opposite side of the green and blue connectors
that is going in this direction if you see it
the potentiometers are on the right side
if they have another reference Driver
They must figure out how you are connected because some go with the potentiometer for the other side
These are the A4988
when they are purchasing the 1.4 Ramps
verify that come with connector
to connect power
and bring the jumper
to be used for bridge
and configure the footsteps of the Driver
You should bring at least 15 of these jumpers to set
double feed point source
I think there is hard to see negative
positive, negative, positive
If only one source cableela twice
D10 is connected to the resistance that heats the hotend
connection to fans
and D8 is connected hotbed
these three outputs are controlled by these power transistors.
what they do is to regulate the heating curve
They are making cuts or delivery to smooth the curve
and the temperature is maintained we have already scheduled
5 is to connect Driver
X- Y- axis Z
extruder 1 and the extruder 2
connection point to each of the motors
and comes twice to the Z axis
That is because some printers use dual engine in the Z axis to either side
the Prusa typically used such axis Z
we are building with the teacher requires just 4 engines
if they want it
and remove the tape and connecting the dissipative
we will be playing go any legs
not to generate them any short
I am using some heatsinks
to verify that both are warming
as we are working with engines of 0.4 A
Driver and these are designed to about 1.5 A
are not warming much so there is no need
but if you have better conéctenlo
with caution not going to be doing a short
a reset button 5Vdc power point
This is going internal, is where we will set up
where we will set up a few steps we will use
the Driver
if they are so loose all
to complete steps if all positions are such a step 1/16
It comes the connection points for final race
and 4 auxiliary points 1-2-3-4
This 4 is used to connect
SD memory display
it's not mandatory
but maybe later I teach them how it's done
we will learn how to configure the A4988 Driver
correctly
not go to waste steps on the engine and we will not heat or damage
There are several options that can be lost steps
as leaving bajita current use in inadequate voltage
set it too fast
or putting on heavily loaded than capable and we will lose steps
Here we will correct one of these options and is
properly calibrated reference voltage
This is extracted directly from the manufacturer's data sheet
and this is the original formula
with this it is that we must always calculate
the maximum current
in our case we will use an engine 0.4A
we will find the reference voltage to calibrate Driver
8 divided by the resistance value of sensitivity
and it tells us that this resistance value is sensed
you must specify in Ω
this is the resistance sensitivity, these two
The most common case these are the R100
It is found in most
equivalent to 0.1Ω
There are several sites on the Internet to calculate the resistors
SMD
Hence the place the R100
0.1 Ω
we must consider that
when we go to the actual calculation
and we'll do
some features of our Driver
A4988
Here we connect the motor voltage
that our case will make 12 Vdc
coil 2
motor coil 1
the working voltage
our Driver
which as we will be between 3 and 5.5 Vdc
so the Arduino works for us perfect is 5 Vdc
a pin to change direction
the pin with the steps that are delivered pulses
and in this we determine the direction
a pin to reset one for sleep
enable one to enable it
and these three we will set
the resolution of the steps you want
here it is, if I leave all three in low
low
we will work Full Step
we do nothing we let the air
if we place
the first high
and leave the other two low
we will use half steps
we should connect this 1
or 5Vdc
a big recommendation that we must consider is that we should not be
connecting and disconnecting the engine with the ignition Driver
because we can damage
here I am directly on the sheet integrated circuit manufacturer
not printed, which is the mistake most
operating voltage plus or minus 2 A
A4988
to 35Vdc
as we connect
This 100μF capacitor mandatory
if they can not hurt, they can damage even the engine
and we must use a microcontroller in this case will be the Arduino
Here we see the resolution that we saw for steps
here it is
current control
Here is the formula recommended by the manufacturer
This is what we use
read the complete data sheet
it's the best that you can do
to understand each of the connection points
how he handles each step
micro configuration
I wanted to show this part
to see if I do understand
if I leave
Full Step complete steps
If I can see here I get up to 70%
Maximum operating our engine
if I use half steps
Here we see that we got to 100
CNC when we leave them in direct steps
to get as much power engines
in this case we do not need a lot of strength
since the structure does not need as in the CNC push to grind
but will simply depositing hot fiber
then you need a lot of strength
but we want to improve the accuracy of the machine
we will place
1/16 of step
all in low as in this case
This Full Step
I'm putting on the jumper
If I put the first high
then I will be according to the table
high, low, low, half steps
I'll place the following
by placing the following is me
high, high, low step that would knockout
and finally I put the third jumper
what would I is high, high, high
It means 1/16 step
I must do this before placing Driver, below these already did
for if you ever want to test with a second extruder
If you are curious they perform tests
then moving a motor on a jumper Take away time will vary
to realize how it works and how much force is in their engines
and how accurate are being
or they will be leaving
clearing formula
I still have that reference voltage is equal to the maximum operating current of my engine
multiplied by the product 8
the resistance value of sensor sensitivity or
maximum current of my engine in this case is 0.4A
by
8
by resistance sensitivity
Mine is an R100
which it is most cases
equivalent to 0.1 Ω
0.1
I made this operation is that
reference voltage is equal
0.32
volt
If we are going to move to millivolts
We run the decimal point three places to the right 1-2-3
I is 320 mv
This is the value we place our reference voltage
using the potentiometers our Driver A4988
as I will use a 1/16 pitch I leave the same
If you were to use full steps as we did with the CNC
I multiply it by 70% I would like 220mV
but right now this is our case
let's see how it's done on Driver
for calibration we will use a voltmeter
and we will connect two points Ramps
one seek a negative if not hard to see here this
aca said positive, negative sign
These are for end of career
then we will connect to half saying negative
there we will connect the multimeter and positive
we use a metal screwdriver blade
or star depending on the potentiometer
and we'll play that point while we go Calibrating
to achieve the connection
in the negative end of multimeter
we connect with a female Cable
and we connect negative to the point of half of the three pins
We leave that to the positive end still and alligator or crocodile connected a
and the other end we connect to the metal part
calibrator screwdriver
so that it can rotate and go censusing
We turn on the multimeter place it in direct current volts
It appears as a solid line
and under an interleaved
that is direct current voltage and displayed on a sine wave voltage is AC
We place direct current voltage
We perform 5Vdc power in this case with the computer
Hence we see that ignited if I give is start to turn on the light
means is connected to 5Vdc
it is not necessary to connect anything
engines or 12VDC power supply is not required
so as we are already connected to the negative
positive we will do through crocodile
and the metal tip
to play the potentiometer
when we play the potentiometer we realize that there is in 0.49 to 0.5
and we can rotate, depending on how we go spinning
it rises 0.6
according to our calculations should give us 0,32
so I turn it
until I mark 0.32
or 320mV
This multimeter is why automatic adjustment was changed to millivolts
there is 320mV
Here they will see mV, millivolt means
and if we had in serious volts .32
In the same way we calibrate the other
as we will use the same engine
if we had a different engine
we would have given an estimate for example 0.5
we should adjust
as this is the case 0.5
or 500mV
0.5Vdc or 500mV
I hope you have been useful this video to learn to calibrate well your Driver
so that is not going to be warm or difficulties or loss of step with engines
and see you next Wednesday in a new video
construction 3D printer
Manito remember to give up on facebook or youtube and see you next
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