speed, and then decelerate such that the final position agrees with the command position, PR. The Z axis accelerates, but before the specified speed is achieved, must begin deceleration such that the axis will stop at the commanded position. All 3 axes have the same acceleration and deceleration rate, hence, the slope of the rising and falling edges of all 3 velocity profiles are the same.

Independent Jogging

The jog mode of motion is very flexible because speed, direction and acceleration can be changed during motion. The user specifies the jog speed (JG), acceleration (AC), and the deceleration (DC) rate for each axis. The direction of motion is specified by the sign of the JG parameters. When the begin command is given (BG), the motor accelerates up to speed and continues to jog at that speed until a new speed or stop (ST) command is issued. If the jog speed is changed during motion, the controller will make a accelerated (or decelerated) change to the new speed.

An instant change to the motor position can be made with the use of the IP command. Upon receiving this command, the controller commands the motor to a position which is equal to the specified increment plus the current position. This command is useful when trying to synchronize the position of two motors while they are moving.

Note that the controller operates as a closed-loop position controller while in the jog mode. The DMC- 13X8 converts the velocity profile into a position trajectory and a new position target is generated every sample period. This method of control results in precise speed regulation with phase lock accuracy.

Command Summary - Jogging

COMMAND

AC x,y,z,w

BG XYZW

DC x,y,z,w

IP x,y,z,w

IT x,y,z,w

JG +/-x,y,z,w

ST XYZW

DESCRIPTION

Specifies acceleration rate Begins motion Specifies deceleration rate Increments position instantly

Time constant for independent motion smoothing Specifies jog speed and direction

Stops motion

Parameters can be set with individual axes specifiers such as JGY=2000 (set jog speed for Y axis to 2000) or ACYH=400000 (set acceleration for Y and H axes to 400000).

Operand Summary - Independent Axis

OPERAND

_ACx

_DCx

_SPx

_TVx

DESCRIPTION

Return acceleration rate for the axis specified by ‘x’ Return deceleration rate for the axis specified by ‘x’ Returns the jog speed for the axis specified by ‘x’

Returns the actual velocity of the axis specified by ‘x’ (averaged over .25 sec)

Example - Jog in X only

Jog X motor at 50000 count/s. After X motor is at its jog speed, begin jogging Z in reverse direction at 25000 count/s.

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USER MANUAL

Chapter 6 Programming Motion • 67

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Galil DMC-13X8 user manual Independent Jogging, Command Summary Jogging, Example Jog in X only