DART Controls DM8000 CONTROL SERIES Instruction Manual page 15

Parameter 14 – Input Triggers / Prescale
This parameter determines how the DM8000 processes the S1 signal input. It specifi ed which
signal edge is used for the measurements and the value of the internal frequency divider or
prescaler. Modes 3 and 4 should only be used if the input pulse rate exceeds the unit's maximum
native pulse rate (see specifi cations for details); otherwise, timing and counting calculations
may become sluggish and unnecessarily inaccurate.
Mode 1: Every Rising Edge, No Prescaler
In this mode, the signal input is measured at every rising edge.
Mode 2: Every Falling Edge, No Prescaler
In this mode, the signal input is measured at every falling edge.
Mode 3: Falling Edge, Prescaler = 4
In this mode, the signal input is measured at every 4th falling edge. This mode is especially
useful when the signal input frequency is beyond the native pulse-per-minute range of the
DM8000. Because unit will automatically compensates for the prescaler, there is no need
to factor in the prescaler value when setting the Display and RPM Reference parameters.
Mode 4: Falling Edge, Prescaler = 16
Same as Mode 3 except the signal input is only measures every 16th falling edge.
Parameter 16 – Counter Reset Confi guration
In counter applications, it is often desirable to have the user or an external signal reset the
counter value to zero or some predetermined value. This parameter specifi es which actions
will cause the counter to reset to the Counter Reset / Preset Value, parameter 27.
Mode 1: Reset Disabled
The counter cannot be reset.
Mode 2: Reset On Button Press
The counter will reset to the Counter Reset / Preset Value, parameter 27, when any of
the user-interface buttons are depressed.
Mode 3: Reset On S2 Input Low (Wired To Common)
The counter will reset to the Counter Reset / Preset Value, parameter 27, when S2 (signal
2) is brought to an electrically low state or wired to the unit's common.
Mode 4: Reset On S2 Input High (Not Wired To Common)
The counter will reset to the Counter Reset / Preset Value, parameter 27, when S2 (signal
2) is brought to an electrically high state (+5V) or left to fl oat disconnected from the unit's
common.
Parameter 20 – Signal Input 1 (S1) Display Reference
This is the number to be displayed when at the user-specifi ed motor Reference RPM. In Rate
Mode, this value represents the numerator of the rate unit such as feet, ounces, or revolutions.
In Time Mode, this value represents the reference time measured in seconds or minutes. If the
desired display is HH:MM, then all values should be entered in minutes. If MM:SS is desired,
then all values should be entered in seconds. In Counter Modes, this value is the reference
count ratio which corresponds to the number of counts which equate to the specifi ed number
of reference pulses, parameter 21.
Parameter 21 – Signal Input 1 (S1) Reference RPM (Reference Pulses in Counter Modes)
This is the reference RPM at which the Display Reference value should be displayed. In Rate
and Time Modes, this value represents the RPM of the encoder to which the Display Reference
corresponds. In Counter Modes, this value is the Reference Pulses which correspond to the
specifi ed number of displayed counter, parameter 21. See applications for examples.
Parameter 22 – Signal Input 1 (S1) Pulses per Revolution
This is the number of pulses per revolution. Value may be from 1 to 9999.
See applications for examples.
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