Omron NJ-series User Manual page 368

Example 2:
When the Button2 variable (assigned to an input signal from a pushbutton) changes to TRUE during
velocity control, the user program in this example decelerates axis 0 (MC_Axis000) to a stop.
The data trace operations and display of the execution results are given below.
1. In data trace processing in System Common Processing 1, TRUE is obtained for Button2.
2. STP_BSY is changed to TRUE in the user program and the Motion Control Function Module per-
forms deceleration processing.
3. In data trace processing in System Common Processing 1 in the next primary period, TRUE is
obtained for STP_BSY and the status of the motion variable is obtained.
4. STP_ACT is changed to TRUE in the user program.
5. In data trace processing in System Common Processing 1 in the next primary period, TRUE is
obtained for STP_ACT.
The command value in the MC Function Module starts changing (B in the following diagram) when
STP_BSY changes to TRUE in the user program and the Motion Control Function Module starts to per-
form deceleration processing. The command value changes stepwise in synchronization with the pri-
mary periodic task. The data trace, however, interpolates the values to connect the values for the
previous and current periods. Therefore, the display shows that the command value for the Command
Velocity motion control variable (MC_Axis000.Cmd.Vel) changes one period early, i.e., when Button2
changes to TRUE (A in the following figure). The display also shows that STP_BSY changes to TRUE
one period after deceleration starts and then STP_ACT changes to TRUE after another period.
Button2
STP_D
STP_BSY
STP_ACT
MC_Axis000.Cmd.Vel
Task period
NJ-series CPU Unit Software User's Manual (W501)
Dotted lines: Command value in MC Function Module
A B
8 CPU Unit Functions
8-41
8