Delta Tau Geo MACRO, User Manual And Reference Manual

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Geo MACRO Drive User and Reference Manual
Absolute Power On Online Commands 161
ABSOLUTE POWER ON ONLINE COMMANDS
$$*
Function: Read motor absolute positions
Scope: Coordinate system specific
Syntax:
$$*
The
$$*
command causes PMAC to perform a read of the absolute positions for all motors in the
addressed coordinate system that require an absolute position read (Ixx10 > 0), as defined by Ixx10 and
Ixx95 for the motor. This command performs the same actions in reading the absolute position data that
are normally performed during the board’s power-up/reset cycle if Ixx80 bit 2 is set to the default of 0.
The action of this command is equivalent to that of a motor-specific
$*
command to each motor in the
coordinate system. Refer to the
$*
command description for the exact actions of this command.
$*
Function: Read motor absolute position
Scope: Motor specific
Syntax:
$*
The
$*
command causes PMAC to perform a read of the absolute position for the addressed motor, as
defined by Ixx10 and Ixx95 for the motor. It performs the same actions that are normally performed
during the board’s power-up/reset cycle.
The
$* command performs the following actions on the addressed motor:
The motor is killed (servo loop open, zero command, amplifier disabled).
If the motor is set up for local hardware encoder position capture by input flags, with bit 0 of Ixx97 set to
0 to specify hardware capture and bit 18 of Ixx24 set to 0 to specify local not MACRO flag operation
(these are default values), the hardware encoder counter for the same channel as the flag register specified
by Ixx25 is set to 0 (e.g. if Ixx25 specifies flags from channel 3, then encoder counter 3 is cleared).
The motor home complete status bit is cleared.
The motor position bias register, which contains the difference between motor and axis zero positions, is
set to 0.
If Ixx10 for the motor is greater than 0, specifying an absolute position read, the sensor is read as
specified by Ixx10 and Ixx95 to set the motor actual position. The actual position value is set to the sum
of the sensor value and the Ixx26 home offset parameter. Unless the read is determined to be
unsuccessful, the motor home complete status bit is set to 1.
If Ixx10 for the motor is set to 0, specifying no absolute position read, the motor actual position register is
set to 0.
Because the motor is killed, the actual position value is automatically copied into the command position
register for the motor.
There are several things to note with regard to this command:
The motor is left in the killed state at the end of execution of this command. To enable the motor, a
$
command should be used if this is a PMAC-commutated motor and a phase reference must be established;
otherwise a
J/
,
A
, or
<CTRL-A>
command should be used to enable the motor and close the loop.
If bit 2 of Ixx80 is set to 1 , PMAC will not attempt an absolute position read at the board power-on/reset;
in this case, the
$*
command must be used to establish the absolute sensor. If bit 2 of Ixx80 is set to 0
(the default), PMAC will attempt an absolute position read at the board power-on/reset.