NORD Drivesystems BU0510 - Manual (Page 69)

6 Synchronous control
BU 0510 GB-3911 Subject to technical alterations 69
6.9.2 Diagonal saw
The diagonal saw is a special case of the "flying saw". Here, no differentiation is made between the slave and
the processing axis. The axis to be synchronised moves at a defined angle (e.g. 20° or 30°) transversely to the
direction of the material. The movement therefore comprises the vectors of a longitudinal and a transverse
direction. Because of this, the angle must also be taken into account for the speed ratio between the master
and the slave.
Fig. 10: Flying saw - Diagonal saw
The speed ratio for the diagonal saw is therefore calculated as:
P608[-xx] / P607[-xx] = (Ü
Gear Slave
* D
Master
) / (Ü
Gear Master
* D
Slave
) * cos(x°)
For the diagonal saw, the advance movement of the saw is therefore proportional to the belt speed. Therefore,
the advance movement of the saw and the belt speed cannot selected independently (as long as the angle is
kept constant). For the "normal" flying saw, the advance movement of the saw is controlled via a separate axis,
independently from the speed of the belt or travel.
Regardless of the setting in parameter P600, the technology function "flying saw" is always executed with
linear ramps and a speed of movement with maximum frequency. Therefore: the return movement of the saw
is always performed with the set maximum frequency, which in general also corresponds to the maximum
speed during synchronous movement.
6.9.3 Offset switching in synchronous operation
In addition to the position setpoint, which can be transmitted from the master to the slave device via the CAN
bus, a relative position offset can be applied to the slave device via the "Increment array". With each 0  1
flank at the relevant input, the position setpoint value can be offset by the value set in the setpoint array
P613[-01]...[-06]. The "Offset" cannot be transmitted directly via a field bus using a "Process Data Word".
Control can be via a digital input or Bus IO.
Master drive
Slave drive
e.g. 30°
V
x
= V
slave
* cos(30°)
V
y
= V
slave
* sin(30°)
V
s
l
a
v
e