
B-63323EN-1/03 1.AXIS CONTROL
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1.9.4 Synchronous Error Check
A synchronous error is monitored at all times. If an error greater than a
certain limit is detected, an alarm is issued, and movement on the axis
is stopped.
When synchronous error compensation is applied, a check covering
positional deviations is also made.
When synchronous error compensation is not applied, a synchronous
error check based on machine coordinates is made.
Check covering positional deviations
When synchronous error compensation is applied, a check covering
positional deviations is also made. An actual machine position shift is
checked, taking servo positional deviations into consideration.
Depending on the magnitude of the synchronous error, an OT alarm for
causing a gradual stop or an SV alarm for immediately turning off the
servo system is issued. This check function is enabled when a value
other than 0 is set as a maximum allowable synchronous error in
parameter No. 1913 or No. 1914. When making a synchronous error
check by using this method, disable synchronous error check based on
machine coordinates (described later), by setting parameter No. 7723
to 0.
- Excessive synchronous error alarm 2 (SV24)
If a synchronous error greater than the value set in parameter No. 1913
is detected, synchronous control alarm 2 is issued.
Until synchronization is established at power-up, the value set in
parameter No. 1913 multiplied by the coefficient set in parameter No.
1910 is used for judgement. If synchronous control error alarm 2 is
issued, the motor stops immediately in the same way as for other servo
alarms. This means that a positional difference between the master
axis and slave axis remains unchanged, disabling alarm cancellation.
In such a case, the synchronous error needs to be corrected manually by
selecting adjustment mode, described later.
- Excessive synchronous error alarm 1 (OT30)
If a synchronous error greater than the value set in parameter No. 1914
is detected, synchronous control alarm 1 is issued.
If synchronous control alarm 1 is issued, the motor is decelerated and
stopped. At this point, synchronous error compensation has yet to be
enabled, so that the synchronous error is reduced by compensation. So,
when the synchronous error falls below the maximum allowable value,
the alarm can be reset. If the alarm cannot be reset, reduce the
synchronous error in adjustment mode as in the case of excessive
synchronous error alarm 2.
Synchronous error check based on machine coordinates
When synchronous error compensation is not applied, a synchronous
error check based on the machine coordinates is made.
The machine coordinates on the master axis are compared with those
on the slave axis. If the error between the master axis and slave axis is