Red Lion MDC User Manual

Page 13

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

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