Galil Motion Control DMC-40 0 Series User Manual

Operation
Commutation Related Velocity
When using sinusoidal commutation and higher speed applications, it is a good idea to calculate the speed at which
commutation can start to affect performance of the motor. In general, it is recommended that there be at least 8
servo samples for each magnetic cycle. The time for each sample is defined by TM, “TM 1000” is default and is in
units of μs per sample or [μs/sample]. TM can be lowered to achieve higher speeds.
Below is the equation that can be used to calculate the desired maximum commutation speed in counts per second
[cts/s]:
Speed
[cts /s ]
=
m×10
6
(TM ×n)
Where,
m
is the number of counts per magnetic cycle [cts/magnetic cycle]
n
is the desired number of (TM) samples per magnetic cycle (8 or more recommended) [samples/magnetic
cycle ]
Example:
Assume that an encoder provides 4000 [cts/rev] and that a motor has 2 pole pairs. Each pole pair represents a
single magnetic cycle.
m
can be calculated as follows:
m=
4000
[cts /rev ]
2
[magnetic cycles]
=2000
[cts /magnetic cycle]
If “TM 250” is set and 8 servo samples per magnetic cycle is desired, the maximum speed in counts per second
would be:
Speed =
2000
[cts/ magneticcycle ]
×10
[μs / s]
6
250
[μs / sample]
×8
[samples / magneticccycle ]
=1,000,000
[cts / s]
Finding Proper Commutation
Using the D3640 requires version 1.1d revision firmware or higher; be sure this is installed on your controller:
http://www.galilmc.com/support/firmware-downloads.php
The 6 commands used for set up are the BA, BM, BX, BZ, BC and BI commands. Please see the command reference
for details.
For detailed information on setting up commutation on the AMP-43640 can be found here:
http://www.galilmc.com/techtalk/drives/wiring-a-brushless-motor-for-galils-sine-amplifier/
1. Issue the BA command to specify which axis you want to use the sinusoidal amplifier on
2. Calculate the number of encoder counts per magnetic cycle. For example, in a rotary motor that has 2 pole
pairs and 10,000 counts per revolution, the number of encoder counts per magnetic cycle would be 10,000/2
= 5000. Assign this value to BM
A5 – AMP-43640 (-D3640) ▫ 238 DMC-40x0 User Manual

Galil Motion Control DMC-40 0 Series Specifications

General

Brand	Galil Motion Control
Model	DMC-40 0 Series
Category	Controller
Language	English