Synchronisation to velocity

Under synchronization to velocity, a slave axis, starting in any state, is synchronized as quickly as possible to a moving master axis. The synchronous velocity of the slave here is given by the master velocity multiplied by the coupling factor.

The synchronization phase of the slave axis is calculated in such a way that the boundary conditions specified by the user are maintained. Calculation and checking of these boundary conditions is carried out under the assumption that the master axis will continue to move without acceleration after the coupling time. If the master axis is not free moving, some overshoot or undershoot of the parameterized boundary conditions may occur.

Example 1:

In the illustrated phase 0 (left) the two axes are moving entirely independently. The future master axis is accelerating to 500 mm/s while the future slave axis is accelerating to -250 mm/s. As the phase changes from 0 to 2 the process of synchronization to velocity in the Universal Flying Saw starts (StartSync = 1) and the set value profile for the synchronization is calculated. This calculated set value profile for the slave is then specified for phase 2 of the slave axis. At the end of phase 2 the slave axis precisely achieves the synchronous velocity, which is the velocity of the master axis multiplied by the coupling factor. From this time on the axes are in the synchronous phase (phase 3). In this synchronous phase the two axes move synchronously in accordance with the coupling factor. The synchronous phase is ended by the uncoupling command. In the illustration, this corresponds to the transition from phase 3 to phase 0. From this time on they are again two independent master axes. The slave axis changes to a master axis online at the uncoupling time. This online change will remove any acceleration or deceleration to which the slave may be subject, thus fixing the velocity of the former slave, with which it will then continue to move without limit.

The phase currently applying to the slave axis can be seen in the nAxisState variable in the cyclic axis interface. (The names of the individual phases in the illustrations do not agree with the values of the nAxisState variable.)

(* Start parameters *)
fMasterVelo     :=  500;
fSlaveVelo      := -250;

(* Coupling parameters *)
fGearRatio      :=  1.0;
fSlaveAcc       := 2500;
fSlaveDec       := 2500;
fSlaveJerk      := 5000;
Synchronisation to velocity 1:

Example 2:

As example 1, but with coupling factor 1.5.

(* Start parameters *)
fMasterVelo     :=  500;
fSlaveVelo      := -250;

(* Coupling parameters *)
fGearRatio      :=  1.5;
fSlaveAcc       := 2500;
fSlaveDec       := 2500;
fSlaveJerk      := 5000;
Synchronisation to velocity 2:

Example 3:

The start of the coupling in the acceleration phase of the future slave.

(* Start parameters *)
fMasterVelo     :=  -500;
fSlaveVelo      := 400;

(* Coupling parameters *)
fGearRatio      :=  1;
fSlaveAcc       := 2500;
fSlaveDec       := 2500;
fSlaveJerk      := 5000;
Synchronisation to velocity 3:

PLC function blocks

The function block MC_GearInVelo is used for the coupling. To end the synchronous phase by uncoupling (online change) the function block MC_GearOut is used.