Siemens SIMATIC S7-200 System Manual page 315

Table 9-26 Motion Commands, continued
Command
Command 122
Execute the motion specified in
the interactive block
Command 123
Capture the Reference Point
offset
Command 124
Jog positive rotation
Command 125
Jog negative rotation
Command 126
Seek to Reference Point position
Command 127
Reload the configuration
Open Loop Motion Control with the S7-200
Description
When this command is executed, the Position module performs the motion
operation specified in the MOVE_CMD field of the interactive block.
In Modes 0 and 1 (absolute and relative motion modes), a single step motion is
S
performed based upon the target speed and position information provided in the
TARGET_SPEED and TARGET_POS fields of the interactive block.
In Modes 2 and 3 (single-speed, continuous operation modes), the position
S
specification is ignored, and the Position module accelerates to the speed
specified in the TARGET_SPEED field of the interactive block. Movement stops
when the command byte transitions to Idle.
In Modes 4 and 5 (manual speed control modes), the position specification is
S
ignored and your program loads the value of speed changes into the
TARGET_SPEED field of the interactive block. The Position module
continuously monitors this location and responds appropriately when the speed
value changes.
When this command is executed, the Position module establishes a zero position
that is at a different location from the reference point position.
Before issuing this command, you must have determined the position of the
reference point and must also have jogged the machine to the work starting
position. After receiving this command, the Position module computes the offset
between the work starting position (the current position) and the reference point
position and writes the computed offset to the RP_OFFSET field of the Interactive
Block. The current position is then set to 0 to establish the work starting position as
the zero position.
In the event that the stepper motor loses track of its position (for example, if power
is lost or the stepper motor is repositioned manually) the Seek to Reference Point
Position command can be issued to re-establish the zero position automatically.
This command allows you to manually issue pulses for moving the stepper motor in
the positive direction.
If the command remains active for less than 0.5 seconds, the Position module
issues pulses to travel the distance specified in JOG_INCREMENT.
If the command remains active for 0.5 seconds or longer, the motion module begins
to accelerate to the specified JOG_SPEED.
When a transition to idle is detected, the Position module decelerates to a stop.
This command allows you to manually issue pulses for moving the stepper motor in
the negative direction.
If the command remains active for less than 0.5 seconds, the Position module
issues pulses to travel the distance specified in JOG_INCREMENT.
If the command remains active for 0.5 seconds or longer, the Position module
begins to accelerate to the specified JOG_SPEED.
When a transition to idle is detected, the Position module decelerates to a stop.
When this command is executed, the Position module initiates a reference point
seek operation using the specified search method. When the reference point has
been located and motion has stopped, the Position module loads the value read
from the RP_OFFSET field of the interactive block into the current position and
pulses the CLR output on for 50 milliseconds.
When this command is executed, the Position module reads the configuration/profile
table pointer from the appropriate location in SM memory and then reads the
configuration block from the location specified by the configuration/profile table
pointer. The Position module compares the configuration data just obtained against
the existing module configuration and performs any required setup changes or
recalculations. Any cached profiles are discarded.
Chapter 9
301