[fadimore]

I have normal design with l297 & l298 connected to bipolar stepper moter
I have 24V 14.6A power supply to control 4 moter
I use stepper motor type AWG22 UL 1007 2.12A /phase 2 Ohm /phase 7.2 mH/phase 200 N.cm Min 1.8 step
I have interface control 4 Axes ,it has a USB to delever 5V to the interface
and a parallel port to computer.
my questions are:
1- is it ok for using 24V power supply 14.6A for 4 stepper motor from l298 (out1 and out2 for one coil and out3&out4 ), there is no volt rate in the specification
of the motor.
2- I bought a board with l298 only then i add l297 to it, i found that he put in4007 ( I know that it is 1A) is it ok for protection the motor 2.12A.
3-can I use 5V from USB to delver to l297&l298 ( from interface card)
or from computer power supply.
4-how can we calculate the current flow from l298 , I have 2 phase motor , are two phases energized in the same time .
5- Vref for 2A /phase is 1.36V Imax=Vref/.68 is it ok
and this will limit the current flow from l298 to motor without what is the power supply is , when we use Ohm'low it must be 4V 2*2=4V
why we use 24v for the motor and how i can know that volt maybe burnt the motor .

[H500]

Yes to most of your questions. 24v is good. The circuit will limit the motor current to Vref/Rsense.

The 4007 diodes won't work. They will get hot and burn out. Use 2 amp or higher diodes with a reverse recovery rating (Trr) of less than 200 nS.

[fadimore]

Thanks for replay H500

[KOC62]

5) Stepper motors are current devices, not voltage. It takes a minimum voltage to cause the motor current to flow. The reason why higher voltages are used is because of the time it takes the current to reach its rated current value. The motor's inductance determines the time constant. The higher the voltage the sooner the current will reach its designed value. The driver circuitry will limit the current to the motor's maximum allowed value regardless of the power supply voltage. Therefore the rule is not to exceed the motor's designed current rating. Also current times voltage equals power. Each motor also has a power limit one should not exceed. A good designer keeps these parameters within their respective limits.

[fadimore]

Thanks Koc62 for your replay , I have 8 wires in this motor , as the diagram I connect two wires together , so I have only 4 wires from the motor I will connect it to driver , the motor connect as bipolar serial , in that way his current is 2.12A , is ok to reach this current or I must limit it to 2A to prevent the l298 , can any one tell me the best way to understand the program EMC2 , from the web, also any one have a designee for l298 & l297 one layer in Eagle and all the file to do the board.

[KOC62]

If the I298/97 is limited to 2A maximum then yes, you must limit it to 2A.
2.12A is close enough.
I used Gecko drivers so I don't have any diy info for your driver.
Not sure what you want to know about EMC2. There is the installation part and the configuration part. You can also look for videos for either part.

[H500]

Bipolar parallel will almost certainly give you better performance. Serial has 4x the inductance.

[fadimore]

Thanks my friends , I use now RL207 diodes 2A , is it OK.
The main question is I have 4 motors with 2 phase ,every phase work with 2A max current , my power supply 24V 14.5A is it enough to feed all motors with it 2 phases in same time? . if all motors work with 2 phases in the same time we must have big current .or they don't work in the same time .

[KOC62]

No, you need fast recovery diodes. I think at least less than 300ns recovery time. You are dealing with fast pulses in that cicuitry area. This also means you need to have a proper circuit board layout. This is not something you can learn in this thread. You also need an oscilloscope to check for oscillations of your circuit, when you are designing your own. Thus your 'scope will need enough bandwidth to view nanosecond pulses.

Have a look at existing circuits. Try this one L297/298 Stepper Driver

[KOC62]

Power supplies needs to be able to supply all the current demands and not drop the output voltage significantly. In your given case of 2A per phase and you have 2 phases per motor then 4 motors could draw 16A, under static conditions. If you stay in this state then yes you need a 16A power supply. In the real world when will this take place? For short periods of time the power supply capacitance may provide 18A - that depends on the storage capacitance of your power supply. Under live running conditions you may not reach that scenario. But I don't know that.

[fadimore]

Thank for replay Koc62 , I ask if you have Skype , my code name fadimore , I want to chat with you if you don't mind and thanks for your information

[KOC62]

No, I don't have skype, nor use chat lines.

[H500]

An example of a fast recovery diode is STTH3R02QRL.

If your power supply is 24v, 14 amps is far more than you will ever need. Even a 5 amp one would be plenty.

[fadimore]

1-Now I have two motor in Y exes work the same , how we can fed ( step. dir. Enb ) from the interface , can we take the same signal from the interface and fed it to the two drivers of the Y exes , or give the same data to the two motors from Emc2 ,
2- I have Rs 0.82 two power resistor in my board but in the diagram it is 0.68 ohm . The formula is Imax = Vref / .68 , we change .68 to .82 .
to calculate Imax
3-Step or Clk it is pulses , I ask about how much HZ I need , and I do it from Emc2 , I need more information about that .

[fadimore]

An example of a fast recovery diode is STTH3R02QRL.

If your power supply is 24v, 14 amps is far more than you will ever need. Even a 5 amp one would be plenty.

Dear sir we have 4 motors Bipolar 2 phase each phase 2A , I ask about the total I need for my stepper motors when it all works at the same time.

[KOC62]

The power supply question I answered earlier in this thread.
Use this link for more info on power supplies... Support
Ask what you do not understand in the above link. It is a long read.

Y-DRIVE:
2 methods;
-Drive each Y-stepper driver signal from the same LPT pin of STEP and DIR. source. If there is not enough drive from the LPT port then you will need a small cmos buffer driver. Each motor needs its own L297/298 circuit.
- OR you may also take another EMC axis like A-axis and in EMC slave this one to the Y-axis. I think EMC can do 6 axis. I have not done this (a dual Y-axis drive) yet, so I'm not talking from experience.

REQUIRED HZ.
This I cannot tell you. It depends on how fast your motor needs to turn. EMC controls your motor speed. How fast your motor turns is dependednt on your lead screw pitch or turns per inch - e.g. IPM of your jogging speed. And also if you use micro-stepping, gears, etc.

EMC will have an upper limit depending on your PC. You might get 26,000HZ or more on some computers. Do a "Latency" test in EMC to get that number.
I don't have an EMC system so I don't know too much about setting it up.

R-sense:
Your sense resistor looks reasonable and I'm assuming you did your math correctly along with your actual Vref in your circuit.

[H500]

Dear sir we have 4 motors Bipolar 2 phase each phase 2A , I ask about the total I need for my stepper motors when it all works at the same time.

I understood your question. With 24v you will most likely get 15 to 30 watts out of each motor. Put an ammeter in series with your power supply and you will see.

[fadimore]

I understood your question. With 24v you will most likely get 15 to 30 watts out of each motor. Put an ammeter in series with your power supply and you will see.

thanks for replay.

you mean max current is 1.25A for each motor ,at 30 watts but i need 2A for full speed , is it ok? , also the motor has two phase each phase 2A max current , you mean that the motor has only 1.25A with 2 phases .

[KOC62]

Perhaps there is a confusion regading what we are looking at or measuring.

In your design you need 2A for full coil current. The sense resistor is calculated to measure the peak coil current and to not exceed 2A. This is true for each motor coil. That is all you need to do for the L297/L298 with regards to current control.

The area where H500 is looking is the power supply current to your 4 motors. This current may not directly relate to your motor coil peak 2A figure because the power supply current is an average of 4 motors. Also, since your motors are not all running full power all the time, the power supply current will not be simply the sum of the motor coil peak current of 2A each. It will be less. How less we can't tell because each cutting of parts will have different motor loads. The Gecko link I supplied earlier gives us an idea of what to expect and is used as a guide for power supply selection.

You could use a 24V @ 10A power supply and monitor the power supply current to your motors, as H500 suggests, and see how much average current you are actually using for different router cutting jobs. Rght now it is just a technical discussion without actual readings to guide us.

I don't have a running CNC to measure such power supply currents so I don't know. I just don't like to buy a power supply that might be too low in current output. Just in case I might starve a motor.

[H500]

Keep in mind that a motor is not a resistor. A drive maintain the set current by switching the power on and off 20,000 times per second with the appropriate duty cycle. 2 amp into a coil will not require 2 amps from the power supply.

I will measure mine and report the results if I feel like it tonight.