7.1. Instructions and communication

The first thing to do is to establish the command and the communication protocol between the computer (PC) and the microcontroller of the application.

7.1.1. Control Commands

The control commands are part of the instructions can you execute the application, they must be in accordance with the characteristics of the engines and mechanical and electrical systems. The minimum parameters that must be set are:

7.1.1.1. Command parameters control

(1) Current through the winding.

Depending on the use of engines, it may not be required that can deliver maximum torque. Since the torque is proportional to the intensity, reducing the value of it, you get the desired motion with lower power consumption and less heating of motors and power amplifiers. The intensity values are set in steps of 1 / 4 of the total, resulting in levels of 125mA, 250mA, 500mA, 750mA and 1000mA.

(2) speed XY axes.

The moving speed XY axes depends on the ratio of steps of step motor and spindle in use. One reason for steps at least 40 ½ steps / s provides a speed of 1mm / s with a 10mm screw step. Speed levels can be set in steps of 1 mm / s, the limit of 50mm / s, thus gives the sequence (1,2,3,4, ... 50 mm / s). The maximum speed of 50mm/so 2000 ½ steps / s is marked by the limitations of the microprocessor in computing the linear interpolation. Substituting the microcontroller by a more rapid or unload some of the functions that can be obtained at higher speeds. The rate set for the other XY is the same, but the actual speed of each depends on the linear interpolation, one may move slower than the other, but always one or both of them operate at the requested speed.

(3) Z-axis speed

Because the functions they perform at the XY and Z are very different, it is necessary that the Z axis functions independently of others. For example, the XY positioning movement for drilling action can be performed quickly, while the movement of boring (Z movement) it's being done slowly. You have to contemplate the possibility of making different speeds for movement on different levels. The criteria for selecting the speeds are the same as mentioned in paragraph (1) for the XY axes, so they are between 1 and 50mm / s in steps of 1 mm / s.

(4) Acceleration of XY axes.

The acceleration is determined by the decrease in the time between two consecutive steps of the motor. The intervals between the steps obtained from a table of previously calculated values, loaded into the microcontroller timer 2 (see Section 5.3). The table values are calculated for the minimum acceleration 5cm/s2. If the data in the table are taken in a staggered, the acceleration increases with the selection. For example: if you take a data if the other does not, the acceleration becomes of 10cm/s2, so get 5cm/s2 intervals, reaching the maximum acceleration of 50cm/s2. The sequence obtained is as follows (5, 10, 15, 20, ... 50cm/s2).

(5) Acceleration Z axis

Following the same criteria as in the previous case, the acceleration levels for the Z axis can be set with the same sequence (5, 10, 15, 20, ... 50cm/s2).