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※ 14.4.6.0.1 BP2P Mode：Basic Point to Point：Phases of the motion profile
This section discusses the detail operation of the same figure in previous section. For simplicity, the
time tag is set to the trigger instance of DI-01.
Phase-0: Standby (or Ready) Phase
Before a trigger to start the P2P operation, the motion controller is at the Standby state. A status signal
P2P Ready can be assigned to any digital output port.
In this state, Pcmd, Vcmd, and Acmd are all zero.
Phase-I: Velocity Ramp Up with S-Curve (Acmd increasing)
In this phase (please check in detail) the Acmd rises from 0 to 10000 rpm/sec within 50 ms; this is the
resulted from the two profile setting parameters:
1.
S-Curve = 50 ms
2.
Ramp-Rate = 100 ms/Krpm
The first parameter S-Curve = 50 ms, means the time required to allow the Acmd reach the pre-defined
Ramp-Rate.
The second parameter Ramp-Rate = 100 ms/Krpm, can be described as the “Time required to
accelerate from 0 to 1000 rpm”.
Check the Acmd rises linearly and the Vcmd rises with S-Curve.
In this phase, between 0 to 50 ms, it is clearly shown that the dominant parameter is S-Curve time.
Phase-II: Velocity Ramp Up linearly (constant Acmd)
After Acmd reaches the desired Ramp-Rate setting, the controller will maintain the Acmd fixed at the
desired ramp rate (acceleration rate) for a certain period depending on the target distance setting. In
this example, it maintains 50ms. During this period, the Vcmd increases linearly.
Check again in detail, the Vcmd rises from 250.0 rpm to 750.0 rpm within this 50 ms period. From the
observation, the ramp rate is calculated as:
Ramp rate = (750.0rpm – 250.0rpm) / 50ms = 500rpm/50ms => 1000rpm/100ms
This matches our Ramp-Rate setting = 100ms/Krpm , that is.
“Accelerate from 0 to 1000rmp, in 100ms”
In this phase, between 50 to 100 ms, it shows that the dominant parameter is Ramp Rate time.
Phase-III: Velocity Ramp Up to Maximum with S-Curve (Acmd decreasing)
In this phase, the Acmd decreases linearly to zero, and the Vcmd will increase to the predefined
maximum speed. Note from the example, this phase sustains from 100ms to 150ms.
Check by simple calculation, that, the total acceleration time required to reach the maximum speed is:
T acc = S-Curve-Time + Ramp-Rate-Time * (Max. Speed / 1000rpm)
In this example,
S-Curve-Time = 50ms,
Ramp-Rate-Time = 100ms,
Max. Speed = 1000rpm,
Results to:
T acc = 50ms + 100ms*(1000rpm/1000rpm) = 150ms
