B8961 and B8962 User Manual
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DA
Distance Absolute
syntax - DA±r, ±r
Units:
selected from the EDIT > SETUP > MECH menu
Range:
unit scaling dependent
Default:
n/a
DA sets the next move position, referenced from absolute zero.The absolute zero
position is established after a Go Home move (GH) and/or with the Set Position
(SP) command.Absolute positioning is typically used in applications where you are
moving to a number of known locations,or if your physical work area is restricted.
Incremental (DI) and absolute moves may be mixed;the control always keeps track
of the absolute position.
Examples:
AC2 DE.5 VE12 DA3
GO Moves to absolute position 3 units.
DA3 GO DA3
GO Moves
once
to absolute position 3 units.
DC
Distance to a Change
syntax - DC±r, ±r
Units:
selected from the EDIT > SETUP > MECH menu
Range:
unit scaling dependent
Default:
n/a
DC is used to define a complex, multiple velocity move profile,or to change an
Output at a specific point during the move.It defines a position at which a change
will occur,“on the fly,” while the motor is still moving.At the specified position you
can change the velocity or change the state of one or more outputs.
The DC command must follow a DA or DI command which specifies the total
move distance.The DC distance is interpreted as an absolute position when used
with DA and an incremental position when used with DI.When used with DI,the
value of DC must be specified as a positive number.When multiple DC’s are speci-
fied within an incremental move (DI),the incremental distance specified by the DC
command is taken from the last DC command,not from the beginning of the
move.See the incremental move examples below for more clarification.The
stan -
dar d
software supports a maximum of 20 DC commands within a move profile.
Application Note: The DC command can only be used when the motor is
moving at constant speed, i.e. not accelerating or decelerating.
Issuing a DC
command (or trigger position) before a previous DC has finished execution is
invalid and can cause unpredicta ble results. For example,the following pro-
grammed move profile is an incor rect use of the DC command: AC1 VE5 DA20
DC1.75 VE7.5 GO
Since the initial acceleration ramp requires 2.5 units of distance to reach velocity
, the DC1.75 is an invalid trigger position and will be ignored.
The following formula ensures the use of valid DC trigger positions:
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