Re: Step/Dierction vs phase drive.

[Paul <paul.corner-at-tesco.net>]

Hi Tim

A small amount of extra work is done in emcmot to produce the pulse train for 
the phase outputs - But this is such a small overhead, you are not going to 
notice it. Note, there are five different pulse generation algorithms that 
can be used with freqmod depending on the value of STEPPING_TYPE in [EMCMOT]

STEPPING_TYPE = 0
 This is the default algorithm if the parameter is not found. Produces a 
fairly even mark/space ratio step & direction output.

STEPPING_TYPE = 1
 Grey code output originally intended to drive a Bridgeport BOSS type motor 
drive directly.

STEPPING_TYPE = 2
 Quadrature phase output for drive electronics that require an A & B type 
signal.

STEPPING_TYPE = 3
 Four phase output for Taig and Microproto electronics.

STEPPING_TYPE = 4
 Step/Dir output using the steppermod binning algorithm. Uneven mark/space 
ratio... Not an option with pre 2.18 BDI releases.

The choice of STEPPING_TYPE will be dictated by the electronics package you 
are using. For most, it will be either 0 or 4.
Whilst on the subject, it is well worth adding a bit of deadband to each axis 
to get rid of any whines and growls when the axis is not moving. Typically, 
this would be equal to one to two steps - I have mine set at 0.0005.

Regards, Paul.


On Sunday 24 Nov 2002 11:14 am, Tim & Heather Smith wrote:
> Does phase driving using freqmod.o use more system resources that using
> step and direction with freqmod.o ??