Galil Motion Control DMC-42 0 Series, Руководство пользователя

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Home Switch Input
Homing inputs are designed to provide mechanical reference points for a motion control application. A transition
in the state of a Home input alerts the controller that a particular reference point has been reached by a moving
part in the motion control system. A reference point can be a point in space or an encoder index pulse.
The Home input detects any transition in the state of the switch and toggles between logic states 0 and 1 at every
transition. A transition in the logic state of the Home input will cause the controller to execute a homing routine
specified by the user.
There are three homing routines supported by the DMC-42x0: Find Edge (
FE
), Find Index (
FI
), and Standard Home
(
HM
).
The Find Edge routine is initiated by the command sequence:
FE A
,
BG A
. The Find Edge routine will cause the
motor to accelerate, and then slew at constant speed until a transition is detected in the logic state of the Home
input. The direction of the
FE
motion is dependent on the state of the home switch. High level causes forward
motion. The motor will then decelerate to a stop. The acceleration rate, deceleration rate and slew speed are
specified by the user, prior to the movement, using the commands
AC
,
DC
, and
SP
. When using the
FE
command,
it is recommended that a high deceleration value be used so the motor will decelerate rapidly after sensing the
Home switch.
The Find Index routine is initiated by the command sequence:
FI A
,
BG A
. Find Index will cause the motor to
accelerate to the user-defined slew speed (
SP
) at a rate specified by the user with the
AC
command and slew until
the controller senses a change in the index pulse signal from low to high. The motor then decelerates to a stop at
the rate previously specified by the user with the
DC
command and then moves back to the index pulse and speed
HV
. Although Find Index is an option for homing, it is not dependent upon a transition in the logic state of the
Home input, but instead is dependent upon a transition in the level of the index pulse signal.
The Standard Homing routine is initiated by the sequence of commands
HM A
,
BG A
. Standard Homing is a
combination of Find Edge and Find Index homing. Initiating the standard homing routine will cause the motor to
slew until a transition is detected in the logic state of the Home input. The motor will accelerate at the rate
specified by the command,
AC
, up to the slew speed. After detecting the transition in the logic state on the Home
Input, the motor will decelerate to a stop at the rate specified by the command,
DC
. After the motor has
decelerated to a stop, it switches direction and approaches the transition point at the speed of
HV
counts/sec.
When the logic state changes again, the motor moves forward (in the direction of increasing encoder count) at the
same speed, until the controller senses the index pulse. After detection, it decelerates to a stop, moves back to the
index, and defines this position as 0. The logic state of the Home input can be interrogated with the command
MG_HMA
. This command returns a 0 or 1 if the logic state is low or high, respectively. The state of the Home input
can also be interrogated indirectly with the
TS
command.
For examples and further information about Homing, see command
HM
,
FI
,
FE
of the Command Reference and
the section entitled Homing in the Programming Motion Section of this manual.
Abort Input
The function of the Abort input is to immediately stop the controller upon transition of the logic state.
NOTE: The response of the abort input is significantly different from the response of an activated limit switch.
When the abort input is activated, the controller stops generating motion commands immediately, whereas the
limit switch response causes the controller to make a decelerated stop.
NOTE: The effect of an Abort input is dependent on the state of the off-on-error function (
OE
Command) for each
axis. If the Off-On-Error function is enabled for any given axis, the motor for that axis will be turned off when the
abort signal is generated. This could cause the motor to ‘coast’ to a stop since it is no longer under servo control. If
the Off-On-Error function is disabled, the motor will decelerate to a stop as fast as mechanically possible and the
motor will remain in a servo state.
Chapter 3 Connecting Hardware ▫ 25 DMC-42x0 User Manual