NORD Drivesystems BU0510 - Manual (Page 66)

POSICON position control for NORD frequency inverters, SK 530E and above
66 Subject to technical alterations BU 0510 GB-3911
The communication channel between the master and the slave and vice versa should be monitored with a
timeout time (P513).
For software version1.6 and higher, the broadcast transmission and reception address can be separately set
via the array parameter P515 for coupling via CANopen
P515
Master
[-03] = P515
Slave
[-02] Broadcast slave address
P515
Master
[-02] = P515
Slave
[-03] Broadcast master address
6.6.3 Slip error monitoring on the slave
Alternatively, the slip error monitoring P630 "Slip Error Pos" can also be enabled for the slave device. If the
synchronous control is enabled, the error between the position estimated from the speed and the actual
position will not be compared, but rather the difference between the setpoint position and the actual position as
long as synchronous operation is enabled.
The monitoring is only valid if the device is enabled and the position control is activated. If the slave is not
enabled, the position of the master may deviate from the position of the slave.
6.7 Notes on reference point runs with synchronous operation
If the slave axis is to be referenced independently from the master axis, the following must be noted:
In synchronised mode, the slave receives its setpoint speed as a specification from the master. If the master is
not running, the slave does not have a setpoint value for the reference point run. Therefor the slave must use
its own parameter set for the reference point run, in which the speed during the reference point run is specified
by F
min
(P104) and F
max
(P105) [F
min
= F
max
= F
ref
]. The frequency addition in P546 "Function Bus Setpoint"
should be switched off. The slave must always be referenced after the master.
For synchronous systems, where the master and the slave cannot be operated separately, a different strategy
must be developed in case of deviation. With incremental position detection the actual position cannot be used
in order to detect a deviation. If there is no deviation, the entire system is referenced, i.e. the slave in
synchronous operation. The reference point run should therefor be performed via the external control unit
according to the following sequence (all steps with a minimum time difference of 20ms):
1. Move entire system to reference point
2. Remove enablement for the master
3. Remove enablement for the slave
4. Perform "Reset Position" for the master (P601
Master
= 0, P602
Slave
jumps by P601
old
-P601
new
)
5. Perform "Reset Position" for the slave (P602
Slave
= 0, P601
Slave
= 0)
For position detection with an absolute measuring system a reference point run is not necessary. Absolute
position detection should be always given preference for systems, e.g. portal lifting gear, in which no deviation
may occur.
6.8 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 parameter P613
"Position" [-01]...[-06]. The offset cannot be transmitted via a field bus using a "Process Data Word". Control
can only be performed via one of the digital inputs or the Bus IO In Bits.