Command
processing
Figure 1 shows the analog torque block mode has the same signal
processing as a velocity loop except that the velocity error signal
(VelErr) is set to VelCmd not to (VelCmd - VelFB) and
that the VelCmd clamp is bypassed. Thus, the analog input goes
through a number of signal processing steps before becoming the
motor torque current command ICmd.
1. Analog differential amplifier with 1200 Hz low pass filter.
2. High resolution A/D sampled at the velocity loop update rate
and added to the ADOffset parameter.
3. ADF0 adjustable low pass filter to become AnalogIn.
4. Bypass the VelLmtHi, VelLmtLo clamp.
5. Velocity error variable VelErr is set equal to VelCmdA.
6. The anti-resonance second order velocity loop compensation
block controlled by the ARF0, ARF1, ARZ0, and ARZ1
parameters to become the FVelErr variable.
7. The proportional and integral velocity loop compensation
block controlled by the KVP and KVI parameters
respectively.
8. And finally through the IlmtPlus and IlmtMinus
current command clamp to become the ICmd motor torque
current command variable.
Although this looks like a large amount of processing, the options
are only there to allow tailoring the response to fit a particular
application.
A-2 MA950
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