Delta RMC151 - Manual (Page 776)

RMC70/150 and RMCTools User Manual
Amplitude
The Amplitude specifies the distance from the center to the peak. The amplitude can be
zero or a positive number. An amplitude of zero is typically only used when it will be
followed by the Change Target Parameter (80) command to ramp the amplitude from
zero to some value.
If the amplitude would cause the target position to exceed the Positive or Negative Travel
Limits, a command error will occur, which will halt the axis if the Auto Stops are set to do
so.
Cycles
The Cycles specifies the number of cycles, in increments of 0.25. Each cycle begins at
the location specified by the Start Location parameter. If Cycles is zero, the sine wave
will repeat endlessly. By specifying various increments of 0.25, you can control whether
the sine wave stops at the bottom, top, or middle. If the Cycles is an integer number,
the sine move will stop at the same location where it started.
A cycle count of 0.25 is not allowed if the Start Location is at one of the peaks, and the
Frequency is zero.
Due to the limits of 32-bit floating point values, the Cycles parameter can be a maximum
of 16 million only if it is a whole number. If it contains a half, such a 45.5, it can be a
maximum of 7,999,999.5. If it contains a quarter, such a 12.25 or 97.75, it can be a
maximum of 3,999,999.75.
Frequency
The frequency can be any value from zero up to the maximum frequency listed in the
table below. The maximum frequency is a quarter of the loop frequency (the loop
frequency is the inverse of the Loop Time). For example, if the loop time is 1000 µsec,
the maximum frequency is 250 Hz.
Loop Time Max Frequency
250 µsec
1000 Hz
500 µsec 500 Hz
1000 µsec 250 Hz
2000 µsec 125 Hz
4000 µsec 62.5 Hz
Fractional frequencies are valid, such as 0.345 or 5.84. Issuing this command with a
frequency of zero is typically only done when it will be followed by the Change Target
Parameter (80) to ramp the frequency from 0 to some value. A frequency of zero is not
allowed if the Start Location is at one of the peaks, and the cycle count is 0.25.
Frequencies below 0.00001 on the RMC75 or RMC150E, and below 0.05 on the RMC75S
and RMC75P, may cause an irregular Target Position when used with the Start Locations
Mid-Pos or Mid-Neg. Test any very low frequencies before using them.
Start Location
The Start Location specifies where on the sine wave the motion should start. When this
command is issued, the Target Position must be at that position, unless a Transition
command has previously been issued to specify how the axis should move to get to the
sine curve. The Start Location options are given below. Notice that each cycle will start
at the location specified by the Start Location.
Start
Location
Description
Auto If the Target Position is at the positive peak, negative peak, or the center,
then the sine move will start there. If it starts at the center, it will move in
the positive direction. See Mid-Pos and Mid-Neg Details below.
756 Delta Computer Systems, Inc.