Red Lion MDC - Manual (Page 25)

Phase
The positive (+) phase of an output indicates that when the alarm becomes
active, the output turns on. When the output is reset it is turned off.
The negative (-) phase of an output indicates that when the alarm becomes
active, the output turns off. The reset condition of the output is the on state.
Boundary or Latched
An alarm programmed for Boundary Output becomes active as determined
by the alarm type (High, Low, Deviation, or Zero Speed). The output stays
active as long as this alarm trigger condition exists, after which the output
returns to its inactive state. A maintained reset on a User Input programmed
for Reset Alarm causes the alarm to stay in its inactive state at all times (see
Program User Menu).
An alarm programmed for Latched Output becomes active as determined
by the alarm type (High, Low, Deviation, or Zero Speed). The output stays
active until it is manually reset by a User Input selected for that function. A
momentary reset causes the output to return to its inactive state provided that
the condition causing the alarm no longer exists. A maintained reset on a User
Input programmed for Reset Alarm causes the alarm to stay in its inactive
state at all times (see Program User Menu).
Normal or Fast Update
The Normal update for the alarm outputs is once each second. This is the
same as the Speed or Ratio display update. The calculation to check for the
alarm condition is made from an average value of feedback measurements
taken over a 1 second period.
The Fast alarm update occurs at an interval less than or equal to 40 msec.
The calculation to check for the alarm condition is made from a single
feedback and/or lead frequency measurement. Since no average is made,
peaks caused by pulse encoder non-linearity (such as differences in the
spacing of teeth on a gear or an unbalanced shaft) can cause the alarm to
trigger early. THE FAST UPDATE SHOULD ONLY BE USED WHEN
FAST RESPONSE IS NECESSARY.
Stop Enabled or Disabled
This is an option that pertains only to the Low alarm and Deviation alarm. It
refers to the alarm function when the MDC is in STOP mode or ramping to or
from STOP mode. When the alarm is Stop Enabled, the alarm functions
normally in stop mode. A low alarm would always be on since zero speed is
always less than or equal to the speed setpoint.
When the alarm is programmed to be Stop Disabled, the alarm is always
inactive in stop mode and when ramping to or from stop mode. The alarm can
only become active after the speed setpoint value has been attained in Master
Mode, or when the ramp up to the setpoint ratio is complete in Follower Mode.
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