6 Synchronous control
BU 0510 EN
technische Änderungen vorbehalten
43
6.8 Comments regarding reference point runs during synchronisation
If the slave axis is referenced independently from the master axis, the following must be noted: The slave obtains
the setpoint speed as a lead from the master. If the master is not running, the slave would not receive the setpoint
for the reference point run. A parameter set in the slave itself must be used for a reference point run where the
speed is set during the reference point run by Fmin (P104) and Fmax (P105) [Fmin = Fmax = Fref]. The frequency
addition in P546 "Function bus setpoint" must be switched off.
The slave must always be referenced after the
master.
In synchronous systems, where master and slave cannot be driven independently from one another, a different
strategy must be developed for occurrences of incorrect positioning. The position actual value cannot be used in
incremental position acquisition to determine incorrect positioning. If incorrect positioning is not present, the entire
system is referenced, i.e. the slave in synchronisation. The reference point run must then be implemented via the
external control with the following steps (all steps with a minimum time offset of 20ms):
1. Entire system travel to reference point
2. Remove enable for master
3. Remove enable for slave
4. Implement "Reset position" for master (P601
Master
= 0, P602
Slave
jumps by P601
old
-P601
new
)
5. Implement "Reset position" for slave (P602
Slave
= 0, P601
Slave
= 0)
In position acquisition with absolute measuring systems, a reference point run is not required. The absolute position
acquisition is recommended in all cases for systems such as e.g. portal lifting equipment where incorrect
positioning must not occur.
6.9 Using offset in synchronous mode
In addition to the position setpoint, which can be transmitted via "CAN bus" from master to slave device, it is
possible to add a relative position offset per "Increment array" in the slave device. With each 0
Æ
1 flank at the
input concerned, the position setpoint can be offset by the value set in parameter P613 "Position“ [01]...[04]". The
offset cannot be transmitted directly via a field bus with the "Process data word". Control can only be implemented
via one of the 7 digital inputs or Bus IO In Bits.
