Emerson FM-3 - Manual (Page 112)

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FM-3 Programming Module Reference Manual
Timed Indexes
A Timed Index allows the user to specify the amount of time in which to perform an index
rather than specifying the Velocity, Acceleration, and Deceleration. The processor in the FM-
3 will automatically calculate the necessary velocity, accel, and decel in order to achieve the
programmed distance in the specified time. A Timed Index can not be compounded into or
out of.
All index types can be specified as a Timed Index, except for Registration type indexes. This
is because a registration index does not have a specified distance or absolute position. During
a registration type index, the registration sensor could activate at any time, and therefore it is
impossible to calculate the necessary velocity, accel, and decel. If Registration type is
selected, then the Time checkbox will become disabled.
Based on the Distance entered (or Position for Absolute indexes) and the Time value
specified, the calculations could result in extremely high Velocities, Accels, and Decels. To
avoid damage to mechanical parts, or potentially dangerous situations, the user is allowed to
enter the Maximum Velocity, Acceleration, and Deceleration used for the calculations. The
results of the firmware calculations will never exceed the maximum values specified.
Figure below shows a screen capture in which the Time checkbox has been enabled. Notice
how the parameters which normally say Velocity, Acceleration, and Deceleration have
changed to say Max. Velocity, Max. Acceleration, and Max. Deceleration. When the Time
checkbox is enabled, these parameters automatically become maximums for use in the
calculations.