Date Code 20010518 SELOGIC Control Equations 7-7
SEL-2020 Instruction Manual
Auto-Message
Operation
Completes
Auto-Message
is Triggered
ISSUE1
D1
Rising Edge Rising Edge
Figure 7.4: Normal Auto-Message Trigger
If the auto-message is not completely processed before the next trigger occurs (for this example,
longer than 10 seconds), then the DLYx bit will be set, as shown in Figure 7.5.
Auto-Message
Operation
Completes
Unsuccessful
Auto-Message
Trigger
Auto-Message
is Triggered
ISSUE1
D1
DLY1
Figure 7.5: Unsuccessful Auto-Message Trigger
The database delay region of the STATUS command response indicates which auto-messages are
unsuccessful. You may need to increase the ISSUE period to eliminate repeated unsuccessful
auto-message triggers.
Another interesting case to consider is when SEL
OGIC Control Equations contain elements that
are cleared by the triggered auto-message. If such an element is set again before the auto-
message processing is complete, further triggering may be disabled. For example, consider the
following trigger and message settings:
ISSUE2 = 1:UMB+2:UMB
MESG2 = \DAC1/\DAC2/
These settings are meant to output any unsolicited messages received on Ports 1 and 2.
However, 1:UMB can become set while \DAC2/ is being processed, leaving the trigger condition
in a set state and precluding any further rising edges; the trigger condition has become disabled.
Figure 7.6 illustrates this problem.
To Next Page
Loading...
