S.B.C. Elettronica S.p.A. - Engineering Division
HPDxxN – High Power User’s Manual
62
Example 9: movement with digital locking and return to origin
(FILE: E002.HPD)
To obtain the following functionality: with reference to the figure below assume there is a
conveyor transporting product and a carriage running parallel to the conveyor and controlled by an
HPD N drive. On receipt of an external start command the carriage is aligned on a zero reference
position (proximity sensor). With a second pulse command, provided by a product detection sensor,
the drive locks on to the conveyor in order to perform an operation on the product at a precisely
defined position; when this operation is terminated the carriage returns to its starting position.
In this case the program makes it possible to execute homing (see chapter 1) after which, on
receipt of the manual command from the sensor, the carriage locks on and covers a distance equal to
the value of Pr87:86; when this distance is reached the drive unlocks and stops according to the
ramp programmed in parameter Pr83. The motor now automatically returns to the origin position
executing a trapezoidal profile with the ramps set in Pr80 and the speed in Pr81. Note that one
motor revolution corresponds to 4096 steps so the value to set in Pr87:86 should correspond to the
number of steps of the motor shaft needed for the carriage to execute the required translation.
The master encoder on the conveyor shaft provides the drive with the necessary position
reference during digital locking.
After having set the default values, program the following parameters:
Pr5=10 (homing speed), Pr31=10, b99.11=1, b40.2=1, b40.12=1, Pr80=trapezoidal profile ramp,
Pr81=trapezoidal profile speed, Pr82=copy of P.51 in digital locking, Pr83=digital locking release
deceleration ramp, Pr84=copy of Pr53 in digital locking, Pr87:86=release dimension in steps
terminal 13 on X3 = pulse command for homing execution
terminal 14 on X3 = axis zero position PNP proximity sensor
terminal 12 on X3 = digital locking sensor pulse command
terminal 12 on X2 = output; high during cycle execution; digital locking commands received during
cycle execution will be disregarded.
The digital locking delay interval can be up to 6.144 msec.
The following auxiliary bits are utilised: b91.10, b91.12. Program (see on next page) :
E
M
MASTER ENCODER
SLAVE MOTOR
PROX SENSOR
SENSOR
CARRIAGE