Siemens SIMATIC FM 351 - Set Actual Value; Cancel Set Actual Value

Modes and Jobs
9-23
FM 351 Positioning Module
C79000-G7076-C351-02
9.5 Set Actual Value / Cancel Set Actual Value
Definition
With the “set actual value” job, you assign a new coordinate to the current encoder
reading. The working range is projected to a different physical range on the axis.
You can calculate the offset of the working range as follows: ACT
new
–ACT
current
.
• ACT
new
is the new specified value
• ACT
current
is the actual value at the time of execution
Requirements
• You have set the parameters for the axis.
• The axis must be synchronized.
Sequence of the Job
1. Enter the coordinate for the actual value (ACT
new
) (AVAL).
– Linear axis:
You must select an actual value so that the software limit switch is still within
the permitted travel range after the job has been called.
The value of the offset resulting from (ACT
new
–ACT
current
) must be less
than or equal to the value of the permitted travel range (maximum 100 m or
1000 m).
– Rotary axis
The following rule must apply to the specified actual value:
0 ≤ actual value < end of rotary axis
2. Set the corresponding trigger bit (AVAL_EN=1).
If the “set actual value” job is sent during a positioning operation, the job is held
back until the operation is completed and is only executed the next time the block
is called.