5. TOOL FUNCTION (T FUNCTION)
The tool positions corresponding to respective tool numbers on the turret
axis are set in the tool registered screen in the unit of least command
increment. By commanding one of T0 to T9999 using tape, MDI, or
memory command, the control unit calculates the moving quantity of the
turret axis from the position of a tool corresponding to this T code on the
turret axis and the present turret axis position. The turret axis is positioned
in such a direction that the absolute value of the moving quantity is less
than 180 degrees. If the absolute value of the moving quantity is 180
degrees, the turret axis is positioned in the plus (+) direction. (Whether
the plus direction means the clockwise direction or not depends upon
Simultaneously when the positioning motion of the turret axis is started,
the commanded decimal 4–digit numeral is sent by the binary code relay
contact. The T code read command signal TF to give the code readout
timing on the machine side is turned to 1 when the time (TMF) preset by
a parameter (No. 3010) has passed after T code signal was sent. Read the
T code signal and perform corresponding motion after reading signal TF
on the machine side.
After completion of corresponding motion, turn signal FIN to 1. Turning
signal FIN to 1 causes signal TF to be turned to 0. Turn signal FIN to 0
after signal TF has been turned to 0. Since signal transfer is just the same
as in miscellaneous function (M function), the T code signal remains held
until a new T code is commanded next.
If the turret axis has already been positioned when signal FIN goes to 0,
the control proceeds to the next block. If the turret axis has not being
positioned yet, the control proceeds to the next block after the turret axis
has been positioned.
If an M code is commanded concurrently in a block to which a T code is
previously commanded, signal FIN should be turned to 1 after all motions
have been completed. When a workpiece is punched by press motion
using a selected tool, a considerable load is applied to the turret.
Accordingly, the turret is mechanically clamped by using shot pins or the
like, in general. Since the mechanical clamping force of shot pins, etc.
is stronger than the clamping force of the servo motor, the turret axis is
usually set to the servo–off condition.
In such a case, the servo–off condition should be released to the servo–on
condition to remove mechanical clamp of shot pins, etc. before starting
the motion of the turret axis. The following description shows an example
of processing to be made on the machine side in such a case.
Assume that interlock signal *ITT of the turret axis is 0 (interlock
condition) and serve–off signal of the turret axis SVFT is 1 (servo–off
condition) when the turret is being mechanically clamped by using shot
pins or the like.
When T0 to T9999 are commanded by tape, MDI, or memory command,
the control unit calculates the moving quantity of the turret axis as
The moving quantity of the turret axis is 0, if T01 is commanded when
tool number 01 is being selected, for example. Let’s consider such a case
that the moving quantity of the turret is not 0, i.e., the turret axis is
positioned. The positioning of the turret is going to start soon after the
T code was sent. However, the axial motion is not commanded because
signal *ITT is 0, and the turret axis remains stopped in practice.
(T AXIS CONTROL)