MM-IM User Guide
16
Hi setpoint
0
t3
Alert Level Deadband
Cleared at t = t3Raised at t = t2Hi Alert:
t2
Alert
Time Deadband
t1
Figure 4: Alert Level and Time Deadband Example
Each AI is independently configurable and has its own HiHi, Hi, Lo and LoLo setpoints and
its own level and time deadband values.
Digital Inputs
Each Medina DI/DID point can be configured with an alert setpoint level.
During DI alert processing, the current value of each DI is compared with the
corresponding alert setpoint value for this DI. Ignoring time deadbands for the moment, if
the current value matches the alert setpoint value, then the
DI Level
alert is raised. If the
current value later changes and no longer matches the alert setpoint value then the
DI
Level
alert is immediately cleared.
As with the AI alerts, the DI alerts can be configured with alert time deadbands. Level
deadbands are, of course, not applicable to digital values.
Counter Inputs
Each Medina PI/PID point can be configured with a Hi Level alert setpoint.
The alerts themselves are handled in exactly the same way as their AI counterparts except
that they do not have level and time deadbands. Level alerts will not be cleared except
when the counter rolls over or is explicitly cleared by a user action.
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