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mycnc:independent_pulse_generator [2018/09/02 14:06]
skirillov
mycnc:independent_pulse_generator [2019/10/04 09:36] (current)
ivan
Line 190: Line 190:
 </​code>​ </​code>​
  
 +====Pulse Generator control for Spindle====
  
 +It is possible to control the spindle speed through the pulse generator. This is done through the independent pulse generator implemented in myCNC, which can be "mixed into" the B axis channel. An independent generator is controlled by writing values ​​to the global variables 8130-8133, as described in the table at the beginning of this page (Register Name / Description table). ​
  
-==== Low level CNC registers ​to control independent pulse generator ​====+When using the GUI elements (buttons, input lines, etc.) it is convenient (and necessary) ​to use the multiplier and frequency registers when setting the generator ​frequency (what you see is NOT what you get, as the multipliers convert the human-read values into real machine values). For example, when the operator changes the value of register #8133 (the preset generator frequency), myCNC software will automatically recalculate the value of this preset frequency ​ while taking into account the preset multiplier and will send this data to the controller.
  
-This is for records only. Users don't have to use low-level access.+When utilizing the Hardware PLC, you MUST use the "​raw"​ value register entry (8130) and independently take into account the multiplier (in the PLC code), as no such helpful conversion is available
  
-^ Register Name ^ Address ^ Description ^ +===Independent Pulse Generator ​Spindle implementation example===
-| EXT_GENERATOR_SPEED | 225 | Generator Frequency, [units] \\ 1 unit 0.000736 Hz  | +
-| EXT_GENERATOR_ACCEL | 226 | Generator ​Acceleration,​ [units] \\ 1unit 0.736 1/c2 |+
  
 +1. Add the code that enables the generator into the Hardware PLC procedure M03.plc (spindle ON procedure). It is convenient to add code to the end of the procedure before the exit(99); line.
  
 +<code C>
 +  // Set the acceleration of the generator
 +  gvarset (8131, 100000); timer = 30; do {timer -;} while (timer> 0); // Delay for 30ms
  
 +// Convert spindle speed reference to frequency.
 +  // The value of the coefficient is selected in such a way as to convert
 +  // 12-bit spindle speed to generator frequency
 +  k = 123456;
 +  freq = eparam * k; // Calculate the raw value of the generator frequency
  
 +  // Send generator frequency value
 +  gvarset (8130, freq); timer = 30; do {timer -;} while (timer> 0); // Delay for 30ms
  
 +  exit (99); // normal exit
  
 +</​code>​
 +
 +2. Add the following code to to enable the generator into the Hardware PLC spindle speed adjustment procedure (SPN.plc controls the speed with which the spindle is rotating).
 +
 +<code C>
 +  // Set the acceleration of the generator
 +  gvarset (8131, 100000); timer = 30; do {timer -;} while (timer> 0); // Delay for 30ms
 +
 +  // Convert reference spindle speed to frequency.
 +  // The value of the coefficient k is selected in such a way as to convert
 +  // 12-bit spindle speed to generator frequency
 +  k = 123456; ​
 +  freq = eparam * k; // Calculate the raw value of the generator frequency by using the multiplier k
 +
 +  // Send the generator frequency value
 +  gvarset (8130, freq); timer = 30; do {timer -;} while (timer> 0); // Delay for 30ms
 +  exit (99); // normal exit
 +</​code>​
 +
 +3. Add the generator shutdown code to the Hardware PLC spindle shutdown procedure (M05.plc turns the spindle OFF). It is also convenient to add this code right at the end of the PLC procedure, before the exit(99); line. 
 +
 +<code C>
 +  // Send generator frequency value
 +  gvarset (8130.0); timer = 30; do {timer -;} while (timer> 0); // Delay for 30ms
 +  exit (99); // normal exit
 +</​code>​
 +
 +
 +{{plc:​mycnc-spindle-pulse-dir-001.png}}
 +
 +{{plc:​mycnc-spindle-pulse-dir-002.png}}
 +
 +{{plc:​mycnc-spindle-pulse-dir-003.png}}
 +
 +In this implementation,​ the pulse-dir generation will be switched ON simultaneously with the classic control (a + 0-10V relay analog output). It is assumed that an unused spindle will be shut off physically by the operator and that the additional control signal will not affect operation. ​
 +
 +<​code>​
 +If the task is to connect both spindles at the same time and switch them during operation
 +(for example, by referencing their tool number), it is necessary to organize ​
 +a more complex PLC procedure, which will be checking the number of the tool, 
 +the value of the global variable or input controller and by this condition ​
 +would include only one of the spindles.
 +</​code>​
 +
 +In this example, we are assuming that the speed of a conventional spindle is 24,000 rpm. This value, respectively,​ is registered as the maximum spindle speed in the settings (//Settings > Config > Technology > Mill/Lathe > Spindle//​). ​
 +
 +{{plc:​mycnc-spindle-pulse-dir-004.png}}
 +
 +At this spindle speed, a full 10V signal must be sent to the analog output, so the "​voltage ratio" coefficient is set to "​1"​ (in the case of, for example, a spindle with an input signal range of 0-5V, this coefficient would be 0.5 to get a 5V signal at maximum speed).
 +
 +When calling the PLC procedures for turning ON the spindle (M03.plc) and changing the spindle speed (SPN.plc), the spindle speed value is stored in the **eparam** variable. ​
 +
 +myCNC controllers have 12-bit registers for PWM and DAC at 0-10V.This means that with a maximum spindle speed of **24000 rpm** and a factor of **1**, the ''​eparam''​ variable will have a maximum value of 4095.
 +
 +Assume that the maximum servo spindle speed is 4,500 rpm. Then the ''​eparam''​ value at a speed of 4500 rpm will be:
 +
 +<​code>​ 4500 * (4095 ÷ 24000) = 768</​code>​
 +
 +The Pulse-Dir input of the servo spindle is set to 10,000 pulses, i.e. the motor shaft will make a full revolution every 10,000 pulses. Then, to achieve a full speed of 4500 rpm, the following pulse rate is required:
 +
 +<​code>​10000 * (4500 ÷ 60) = 750 000</​code>​
 +
 +The register RAW value for 750kHz (750,000Hz) will therefore be calculated as follows:
 +
 +<​code>​ 750000 ÷  0.0014549 = 515499347</​code>​
 +
 +If the maximum speed corresponds to the ''​eparam''​ value of "​768",​ then the value of the coefficient to obtain "​515499347"​ will be calculated as follows:
 +
 +<​code>​ 515499347 ÷ 768 = 671223</​code>​
 +
 +By setting these values ​​in the M03.plc and SPN.plc procedures, we will generate the required 750 kHz frequency when the spindle speed is set to 4500, as well as smooth frequency control over the entire range from 0 to 4500 rpm.
 +
 +
 +===A method for evaluating the required acceleration of a generator===
 +
 +One unit of the generator acceleration is, by a very rough approximation,​ 1 impulse / s2. This means that with such an acceleration,​ the generator “accelerates” ​ to a frequency of 1 Hz in 1 second. If, in our case, the maximum frequency is 750,000, then the acceleration must be equal to the same value in order to “accelerate” to this frequency in 1 second.
 +
 +===Test code for spindle start-up and spindle speed adjustment procedures===
 +
 +<code C M03.plc>
 +//Turn on Spindle clockwise
 +#include pins.h
 +#include vars.h
 +main()
 +{
 +  command=PLC_MESSAGE_SPINDLE_SPEED_CHANGED;​
 +  parameter=eparam;​
 +  message=PLCCMD_REPLY_TO_MYCNC;​
 +  timer=0;​do{timer++;​}while (timer<​10);//​pause to push the message with Spindle Speed data
 +
 +  timer=0;
 +  proc=plc_proc_spindle;​
 +
 +  val=eparam;
 +  if (val>​0xfff) {val=0xfff;​};​
 +  if (val<0) {val=0;};
 +
 +  dac01=val;
 +
 +  portclr(OUTPUT_CCW_SPINDLE);​
 +  portset(OUTPUT_SPINDLE);​
 +
 +  gvarset(7370,​1);//​Spindle State
 +  timer=30;​do{timer--;​}while (timer>​0);​ //
 +  gvarset(7371,​eparam);//​Spindle Speed Mirror register
 +
 +  //​gvarset(7372,​0);//​Mist State
 +  //​gvarset(7373,​0);//​Flood State
 +
 +
 +  gvarset(8131,​ 500000); timer=30;​do{timer--;​}while(timer>​0);​ //30ms delay
 +  k=671223; ​
 +  freq=val*k; //calculate the RAW frequency
 +  if (freq>​515499348) {freq=515499348;​};​
 +  gvarset(8130,​freq);​ timer=30;​do{timer--;​}while(timer>​0);​ //30ms delay
 +
 +
 +  //delay after the spindle was turned on
 +  timer=spindle_on_delay;​
 +  do{timer--;​}while (timer>​0);​ //delay until the spindle reaches the given speed
 +
 +  exit(99);​ //​normal exit 
 +};
 +</​code>​
 +
 +<code C SPN.plc>
 +#include vars.h  ​
 +//set the Spindle Speed through DAC
 +main()
 +{
 +  val=eparam;
 +  dac01=val;​ //​send the value to the DAC register
 +
 +  //Change the Spindle State
 +  gvarset(7371,​eparam); ​ timer=30;​do{timer--;​}while (timer>​0); ​ //30ms delay
 +
 +  s=gvarget(7370);​
 +  if (s!=0) //if spindle should be ON
 +  {
 +    k=671223; ​
 +    freq=val*k; //calculate the RAW frequency using the multiplier
 +    if (freq>​515499348) {freq=515499348;​};​
 +    gvarset(8130,​freq);​ timer=30;​do{timer--;​}while(timer>​0);​ //30ms delay
 +  };
 +  exit(99);//​normal exit 
 +};
 +
 +</​code>​
 +
 +
 +==== Low level CNC registers to control independent pulse generator ====
 +
 +This is for records only. Users don't have to utilize these settings which can be altered only by having low-level access to the controller.
 +
 +^ Register Name ^ Address ^ Description ^
 +| EXT_GENERATOR_SPEED | 225 | Generator Frequency, [units] \\ 1 unit = 0.000736 Hz  |
 +| EXT_GENERATOR_ACCEL | 226 | Generator Acceleration,​ [units] \\ 1unit = 0.736 1/c2 |
  
 Independent pulse output can be used for - Independent pulse output can be used for -
mycnc/independent_pulse_generator.1535911608.txt.gz · Last modified: 2018/09/02 14:06 by skirillov