Error Handling
06/2005
Danaher Motion
160 Rev
E
M-SS-005-03l
SYSTEM.ERRORPRINTLEVEL
only affects printing to the message log
window. Fatal faults and errors continue to be logged, and can be viewed
using
?ERRORHISTORY
.
ERRORPRINTLEVEL
applies only to
asynchronous errors. Synchronous errors are not affected.
11.1.3. Terminal
Context
Terminal context is similar to task context, as commands are processed
similarly. The error action is different from a task as there is no interpreter to
be idled when an error occurs.
11. 2
W
ATCH
D
OG
The MC provides a WatchDog timer to help determine if the host PC
connection is operational. To use the WatchDog, configure the MC to expect
WatchDog messages. During normal operation, the host PC must reset the
WatchDog timer before the end of the specified interval to avoid a WatchDog
fault.
Normally, the WatchDog is cycled indirectly through fast I/O.
WDCYCLE
directly resets the WatchDog, but this is not recommended because it
requires 15 to 20 ms per WatchDog cycle. Given that WatchDog timers are
often reset every 100 ms, this implies that the WatchDog function could
consume 15 to 20% of the MC processor time. Events triggered by the fast
I/O can avoid this problem. The following commands configure the MC to
expect WatchDog cycles:
WDINIT
establishes a WatchDog timer. When selecting the reset time, it
should be long enough that the WatchDog function does not consume undue
amounts of processing time. The time also should be short enough so that if
the communication link between MC and host is lost, the MC can shut the
axes down in a timely manner. Different applications require different times,
but 100 to 1000 ms (<
Cycles
> = 5 to 50) are commonly used.
WDCYCLE
cycles the WatchDog timer.
WDDELETE
deletes the WatchDog timer.
WDDELETE
is seldom used in
normal operation because once a WatchDog timer is started, it is seldom
stopped intentionally.
