7.1.1.2. Shares of control commands

So far only dealt with the issue of parameters, which are the constants that define the shape of the movement of the engines. The parameters will only assign a value to the corresponding variable without causing any action by the system. On the other hand, there are actions that produce some kind of movement. In the implementation of actions is where the parameters. The minimum actions that have to do the system are:

(1) Process XY engines.

The steps in the XY motors down a motion in the XY plane. By this action can establish a simple movement of one of the engines, the X or Y, or a combined movement of both engines simultaneously. The combined motion is made by linear interpolation, so that both start and stop at the same time, regardless of the steps you have to give each. Speed marked on the parameters only reached the engine has to give the greatest number of steps, while the other will be delayed for synchronized movement. The result of linear interpolation motion in a straight line from the current position to the new position (xy), indicated in relative terms. The data can be delivered are bounded to a 16-bit integer variable, with the reason not to complicate the operations in the form of linear interpolation. Data can be positive or negative, indicating a forward or reverse direction. The data range is between (-32768 and 32767), representing each unit a half step, which is a spindle 10mm step linear movement of (32767 ½ steps) / (400 ½ steps / cm) = 81.9175 cm . If the path of the linear system is higher than 0.82m, and the necessary movement exceeds this value, may be performed twice, moving the axles each portion of the total. Thus, the route that you can get is unlimited.

(2) motor Steps Z.

The range determined for this engine is the same as the XY motors, -32768 to 32767 steps ½ (½ linear pitch = 0.025mm). The Z motor movement is performed independently, ie can only be moved while the engine XY Z is stationary or vice versa.

(3) Initialization of the axes to zero.

Because you have no reference to the position in which the axes, as it works in open loop when the system starts or when an error occurs, it is desirable to move the axes to a reference position . The zero position can be obtained using sensors limit switches. The action is to approach the reference position until the corresponding sensor is activated, at which point the engine stops, leaving the axle on the position of the sensor.

(4) Error.

The only transmission is performed in reverse mode, the computer application is the indication of error. An error indicator is very necessary, it alerts the computer, which for the transmission of instructions and has been an unexpected event, usually freezing, but could be destructive. The error indications may occur for two reasons: first, that a skate any axis sensor reaches a limit, in this case the system crashes, the axes are stopped to avoid collision with the skate bench, and the error occurs. The second happens on a voluntary basis by the handle, pressing the stop button system, this may be linked to avoid a collision, a break, in short, any preventive measure. When an error the current instruction crashes occur without completion. An error can be caused by a collision with a loss of steps (loss of the current position) as is necessary to initialize the system. After an error the only command that accepts the initialization (I) to position the new axis at zero.

Since this is a limited number of commands, these can be reduced to an initial letter that you define. Through the character in the command can establish communication between the computer and application. A summary table of commands and related values is shown in Table 7.1.