Dynomotion

Group: DynoMotion Message: 12877 From: d_triezenberg Date: 2/27/2016
Subject: Parameter StepperAmplitude

I am running KFLOP/KSTEP and want to be sure that I am correctly setting the value of parameter StepperAmplitude.   An earlier discussion on this forum states that KSTEP is an open loop control, so it makes sense to set StepperAmplitude for the desired low frequency voltage and Lead for boost at higher running speed.  I am working under the assumption that StepperAmplitude has modulus 256 (i.e., 8 bit resolution) but can no longer find the article in the documentation that would confirm this.   I believe that the same article explains the relation of parameter Lead to the lead function time constant.

My steppers are 2.8 ohm/phase and are rated for 1.5 amps.  I use a 24 volt supply.  So if modulus 256 is correct, the value for StepperAmplitude should be

(2.8 ohm * 1.5 amp)/(24 volts) * 256 = 45

Questions are:

1. Where is the article that I vaguely recall, on the scaling of StepperAmplitude and Lead?

2. Is my calculation of StepperAmplitude correct?

3. What is the function of the current setting jumpers on the KSTEP board ? (I have them set at 1.25 amp)

Dave
Group: DynoMotion Message: 12880 From: Tom Kerekes Date: 2/27/2016
Subject: Re: Parameter StepperAmplitude
Hi Dave,

StepperAmplitude is not used with Step/Direction drives like KStep. Use the Jumpers on KStep to set the current amplitude. KStep has internal current feedback chopper circuits so the appropriate voltage amplitude and phase lead will occur to achieve the desired currents.

SnapAmp uses a different mode of operation where there are no "steps". Instead KFLOP commands sinusoidal motor currents directly. This is referred to as "Microstep" mode and uses the StepperAmplitude setting. 

Sorry for the confusion. 

TK

On Feb 27, 2016, at 7:48 AM, d.triezenberg@... [DynoMotion] <DynoMotion@yahoogroups.com> wrote:

 

I am running KFLOP/KSTEP and want to be sure that I am correctly setting the value of parameter StepperAmplitude.   An earlier discussion on this forum states that KSTEP is an open loop control, so it makes sense to set StepperAmplitude for the desired low frequency voltage and Lead for boost at higher running speed.  I am working under the assumption that StepperAmplitude has modulus 256 (i.e., 8 bit resolution) but can no longer find the article in the documentation that would confirm this.   I believe that the same article explains the relation of parameter Lead to the lead function time constant.

My steppers are 2.8 ohm/phase and are rated for 1.5 amps.  I use a 24 volt supply.  So if modulus 256 is correct, the value for StepperAmplitude should be

(2.8 ohm * 1.5 amp)/(24 volts) * 256 = 45

Questions are:

1. Where is the article that I vaguely recall, on the scaling of StepperAmplitude and Lead?

2. Is my calculation of StepperAmplitude correct?

3. What is the function of the current setting jumpers on the KSTEP board ? (I have them set at 1.25 amp)

Dave