For all Critical errors the following rule applies: following a critical error indication, it is probable that the position
and rotation speed of the encoder are wrong. The drive system must be placed in a safe condition.
7.6.5
Recommend fault handling
Within the previous chapters a summary is shown of all the different information which
the motor feedback system provides to monitor and analyze operation and error condi‐
tions of the drive system.
For non-safety applications it is recommended to watch the fast position information
only. As long as the fast position is valid there is no loss of accuracy in motor controlling
and the system can ride through any error situation within the set tolerances.
The simplest fault handling in this case would only watch the
DEV_THR_ERR
signal (see
). When set to “1” the maximum tolerable deviation between the mechani‐
cal and the calculated position value is violated and the allowed fast position error is
exceeded. In this case the application has to be stopped and brought into safe condi‐
tions, respectively. The tolerance for this signal can be adjusted by the user via fast
position acceleration boundary (MAXACC register;
) and the fast position
estimator deviation (MAXDEV register;
).
This information is also available within the EVENT_H register Bit 1 (DTE;
as well as the online_status_d/high byte at Bit 1 (
) which is a copy of the
EVENT_H-register. The online_status is non-persisting information while the EVENT_H
register content is latched. Online Status
For root cause investigations of an error situation further encoder messages can be
read.
It is further recommended to monitor the
estimator_on
signal and/or POS flag, which
are provided as a further digital output of the DSL-master (see also
). It
indicates that the fast position value is invalid and the current value is supplied by the
position estimator (see
). For statistical analyses of the stability of the
position reading this signal can be monitored in reference to a defined time base. In
this case it is possible to identify changes of the position reading behavior of the sys‐
tem.
This information is also available within the EVENT_H-register Bit 3 (POS;
)
as well as the online_status_d/high byte at Bit 3 (
), which is a copy of the
EVENT_H register. The online_status is a non-persisting information, but the EVENT_H
register content needs to be cleared after reading.
Information like SUM (high byte/Bit 6) or even QMLW (low byte/Bit 2) at the online_sta‐
tus_d or EVENT_H/L registers shall not be solely used for fault handling. These are
summary information where several different contents are combined by OR, which
sometimes only report a line or link quality status (i.e. quality monitoring at MAS‐
TER_QM;
).
During start-up of the motor feedback system (either due to power-on or due to a reset
command) internal checks are carried out and some notifications are set that need to
be treated different to normal operation conditions.
While the motor feedback system is powered-down or in reset multiple notifications and
errors will be shown in the online status. These are set by default and they are cleared
after the motor feedback system starts sending correct information to the DSL-master.
If the online status still contains transmission or position fault indications after the
specified initialization time has elapsed reactions have to follow the recommendations
of the previous chapters.
7
CENTRAL FUNCTIONS
84
T E C H N I C A L I N F O R M A T I O N | HIPERFACE DSL
®
8017595/ZTW6/2018-01-15 | SICK
Subject to change without notice