Control Techniques Mentor MP User Manual

Menu 3
Parameter
structure
Keypad and
display
Parameter x.00
Parameter description
format
Advanced parameter
descriptions
Serial comms
protocol
Performance
44 Mentor MP Advanced User Guide
www.controltechniques.com Issue Number: 4
The speed ripple can be quite high, for example with a 4096 line encoder the speed ripple is 14.6 rpm, but this does not define the resolution of the
speed feedback which is normally much better and depends on the length of the measuring period used to obtain the feedback. This is shown in the
improved resolution of the value accessible in Pr 3.02 {di05, 0.40} which is measured over 16 ms, i.e. a resolution of 0.23 rpm with a 4096 line
encoder. The speed controller itself accumulates all pulses from the encoder, and so the speed controller resolution is not limited by the feedback, but
by the resolution of the speed reference.
If a SINCOS encoder is used from an option, the encoder speed ripple is reduced by a factor of 2(
2-Interpolation bits
).
For example, with the nominal 10 bits of interpolation information, the speed ripple is reduced by a factor of 256. This shows how a SINCOS encoder
can reduce noise caused by encoder quantization without any filtering in the speed feedback or the current demand, so that high gains may be used
to give high dynamic performance and a very stiff system.
The speed error is the difference between the final speed demand and the speed feedback in rpm. This does not include the effect of the D term in the
speed controller feedback branch.
The output of the speed regulator is a torque demand given as a percentage of rated motor torque. This is then modified to account for changes in
motor flux if field weakening is active, and then used as the torque producing current reference.
If the speed feedback (Pr 3.02 {di05, 0.40}) is at or below the level defined by this parameter in either direction the Zero speed flag (Pr 10.03) is 1,
otherwise the flag is 0.
3.03 Speed error
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 11111
Range ±SPEED_MAX rpm
Update rate 4 ms write
3.04
{di06, 0.41}
Speed controller output
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
1 11111
Range ±TORQUE_PRODUCT_CURRENT_MAX %
Update rate 4 ms write
3.05 Zero speed threshold
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Range 0 to 200 rpm
Default 30
Update rate Background read
3.06 At speed lower limit
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Range 0 to 10,000 rpm
Default 5
Update rate Background read
3.07 At speed upper limit
Coding
Bit SP FI DE Txt VM DP ND RA NC NV PT US RW BU PS
111
Range 0 to 10,000 rpm
Default 5
Update rate Background read

Control Techniques Mentor MP Specifications

General

Brand	Control Techniques
Model	Mentor MP
Category	DC Drives
Language	English