help with an old servo

[yassser]

Hello,

I have an old western German CNC machine that I wanted to renew , the problem is there is no manuals at all for any of its components , and I'am an inexperienced student .

Is there a safe way to know how to operate its servos.

each servo has a tachogenerator output to the control unit , and an input that has many pins , so would it be safe to apply different binary values on these pins and see how it works.

another thing , on the servo plate ther is:

Ieff:22A , I (with a cap sign on its top) = 200A
U(with a cap sign on its top)=170V
UN = Bremse 24V

what does that mean

thanks very much in advance.

[Al_The_Man]

I believe Bremse is brake.
Modern DC motor controller do not use the tach any more so you could disregard that if using a different drive/controller.
The item with many pins is probably an encoder, of which often were quadrature pulse differential. In the absence of documentation you may have to do some reverse engineering on the encoder to determine the pins, look to see if the encoder has a part # or make.
Al.

[yassser]

thanks very much for the fast response , I'll try and may be ask more questions later.

[yassser]

one more beginner question , how can I have a 170V DC supply from the 220V AC outlet , can a voltage regulator be used for that .

and what does the cap symbol on the I , U mean.

[Al_The_Man]

I would say it is 20a continuous and 200a peak before any damage occurs.
Ideally if you had 120vac then rectified it would make a suitable supply for the motors.
You need a 240 to 120v transformer.
Al.

[yassser]

hello,

another question , I'm using pwm to control the dc motor speed , and using the H bridge to transform the signal to a high power signal , the H bridge I know can give up to 3A , the motor I have takes 25A , Is there a H bridge that can support this , I searched the internet but I didn't find it.

If not , would it be possible to use few 3A H bridges and give them the same signal and combine all there current values to run the motor.

Regards.

[Al_The_Man]

You can use descrete JFET or IGBT components to make a higher power bridge.
You should find a few designs out there on the web.
Al.

[yassser]

what about using more than one 3A H-bridge , have any one tried that before , because I'm not very experienced in electronics and I don't want to get stuck in it .

[yassser]

why is this code not working?

when (set_point < feed_back) , the if statement is executed.

but when (set_point > feed_back) , the it doesn't.

and it is working on the sw debugger but not on the breadboard.

//---------------------------------------------------------

unsigned int set_point , feed_back;
signed int current_duty;

void InitMain() {

PORTA = 0;
TRISA = 0xff; //PORT A FOR A/D CONVERSION

/*ADCON0 = 0x00000001; //PORT A WORKS AS AN ANALOG INPUT NOT DIGITAL */

PORTE = 0; // set PORTE to 0
TRISE = 0; // designate PORTE pins as output
PWM1_Init(20000); // Initialize PWM1 module at 20KHz

}

void main() {
InitMain();

ADC_Init();
PWM1_Start(); // start PWM1

while (1) {
set_point = ADC_Read(0);
feed_back = ADC_Read(1);

if(set_point<feed_back)
{
PORTE.B1=0;
PORTE.B2=1;
}

else if(set_point>=feed_back)

{
PORTE.B1=1;
PORTE.B2=0;
}

current_duty = set_point - feed_back;
current_duty = current_duty * (255.0/1023.0) ;
current_duty = abs( current_duty );

PWM1_Set_Duty(current_duty); // Set current duty for PWM1
}
}