MDC Manual 1109KB - Red Lion Controls

OVERFLOW INDICATION
An input frequency overflow occurs in the normal operating mode when
the input frequency specifications are exceeded. The MDC continuously
displays “FB FREQ OVERFLOW”, or “LD FREQ OVERFLOW” when the
respective input frequency exceeds specifications.
A second type of overflow is an Indication Display overflow. The MDC
flashes the word “OVERFLOW” in the appropriate display when the
overflow condition occurs. A display overflow occurs if the capacity of the
display is exceeded. This can occur when DSP UNIT (Maximum Display
Units) is scaled near the limit and the motor speed exceeds the scale value
MAX RPM FB (Maximum Feedback RPM). For example, if DSP UNIT is
set to 99999 and MAX RPM FB is set to 1750, the SPEED display overflows
if the motor exceeds 1750 RPM.
A third type of overflow occurs in the Program Scaling Menu. If a PPR
(Pulses per Revolution) or MAX RPM value is entered which causes the
Maximum Equivalent Frequency (FB or LD) to exceed 20971 Hz, a Scaling
overflow occurs. The display flashes “OVFLW” in place of the numeric
value and a new value is required. The equivalent frequency can be
determined by:
Maximum Equivalent Frequency =
PPR x MAX RPM
60
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