Dynomotion

Group: DynoMotion Message: 12139 From: tapiolarikka Date: 8/22/2015
Subject: Connecting stepper motor?
Hi Tom,

How is a stepper motor driver connected to Kanalog?

To opto-outs? How do I define the step/dir bits?

Rgds,
Tapio
Group: DynoMotion Message: 12140 From: embraced338 Date: 8/22/2015
Subject: Re: Connecting stepper motor?
I believe you will have to use the JP5 (RJ45 connector) on the KFLOP to achieve this.

See this page: Step and Direction Setup

 

 
Group: DynoMotion Message: 12188 From: tapiolarikka Date: 8/31/2015
Subject: Re: Connecting stepper motor?
Hi Tom,

I read the step&dir setup but found no solution that I'd be comfortable with.

I have drive like this: http://www.omc-stepperonline.com/24-phase-nema-23-stepper-motor-driver-2450vdc-15a45a-256-microstep-m542t-p-293.html

Manual says that step/dir high pulse should be >3.5VDC

My problem is that JP5&JP7 are taken by Kanalog and JP6 taken by Konnect.

Kanalog has encoders 0-6 in use.

JP4 is empty, apart from the ceramic capacitor as per Konnect instructions.

Splicing the JP5 cable to get access to pins 7&8 is not very appealing

JP4-15&16 with voltage dividers is even less appealing. 

This stepper is a rotary pneumatic cylinder replacement that will run from limit to limit, always outside coordinate system.

As test I got the motor running by connecting the drive Step- to FET 2 and doing

If Time_sec()> t0+0.001
 {
         SetStateBit(154, !ReadBit(154))
         t0=Time_sec();
 }

This gives me 70-80% of required speed but I'd prefer to be able to do Jog().

Is there a way to mux step/dir pins to opto-out? I have four of them unused.

-How fast can the optos toggle?

-How fast can the FETs toggle?

-How fine resolution does the Time_sec() have?
     meaning how low t0+? can I use if the step/dir signals can't be muxed?

Rgds,
Tapio

 
Group: DynoMotion Message: 12199 From: Tom Kerekes Date: 9/3/2015
Subject: Re: Connecting stepper motor?
Hi Tapio,

Sorry for the delay I missed this.

Question:  What do you mean by:  "JP4-15&16 with voltage dividers is even less appealing"

I believe that should work as an open collector drive without any problems.  Because the drive input has an LED and resistor in series it is ok to connect the + terminal to +5V and the - terminal to JP4 pins 15 or 16.

HTH
Regards
TK 




Group: DynoMotion Message: 12200 From: Tapio Larikka Date: 9/4/2015
Subject: Re: Connecting stepper motor?

Hi Tom,
 
"JP4-15&16 with voltage dividers is even less appealing" means that I tought inputs to JP4-15/16 be above 3.3V.
 
Today I tried connecting connectig +5V->drive->JP4. With IO screen I see that bits 24&25 get configured as outputs and bit 25 toggles according to direction change but I
don't get movement. I can measure 3.6/0.11 VDC between drive input(JP4 side of the input) and ground, according to the state of the output.
 
It seems that the signal is not quite strong, missing perhaps few tenths of volt.
 
Moving the wires back to FETs I again have movement.
 
Rgds,
 
Tapio
 
 
 
----- Original Message -----
Sent: Friday, September 04, 2015 9:13 AM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Sorry for the delay I missed this.

Question:  What do you mean by:  "JP4-15&16 with voltage dividers is even less appealing"

I believe that should work as an open collector drive without any problems.  Because the drive input has an LED and resistor in series it is ok to connect the + terminal to +5V and the - terminal to JP4 pins 15 or 16.

HTH
Regards
TK 




Group: DynoMotion Message: 12201 From: TK Date: 9/4/2015
Subject: Re: Connecting stepper motor?
Hi Tapio,

Are you using open collector mode?  OutputChan0=3 not 11. 

Those voltages would indicate the drive is seeing:

5 - 3.6 = 1.4V

and

5 - 0.11 = 4.89V

So the drive input is probably never quite turning off. 

On the Digital I/O screen you can simulate the open state by turning off the output. The voltage should then go to about 3.85V and turn off the drive input. 

Regards
TK

On Sep 4, 2015, at 9:10 AM, 'Tapio Larikka' tapio.larikka@... [DynoMotion] <DynoMotion@yahoogroups.com> wrote:

 



Hi Tom,
 
"JP4-15&16 with voltage dividers is even less appealing" means that I tought inputs to JP4-15/16 be above 3.3V.
 
Today I tried connecting connectig +5V->drive->JP4. With IO screen I see that bits 24&25 get configured as outputs and bit 25 toggles according to direction change but I
don't get movement. I can measure 3.6/0.11 VDC between drive input(JP4 side of the input) and ground, according to the state of the output.
 
It seems that the signal is not quite strong, missing perhaps few tenths of volt.
 
Moving the wires back to FETs I again have movement.
 
Rgds,
 
Tapio
 
 
 
----- Original Message -----
Sent: Friday, September 04, 2015 9:13 AM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Sorry for the delay I missed this.

Question:  What do you mean by:  "JP4-15&16 with voltage dividers is even less appealing"

I believe that should work as an open collector drive without any problems.  Because the drive input has an LED and resistor in series it is ok to connect the + terminal to +5V and the - terminal to JP4 pins 15 or 16.

HTH
Regards
TK 




Group: DynoMotion Message: 12202 From: Tapio Larikka Date: 9/4/2015
Subject: Re: Connecting stepper motor?

Hi Tom,
 
I have FPGA(STEP_PULSE_LENGTH_ADD)=62 + 0x40;
in init and OutPutChan=1 to get Step/Dir on JP15&16 (acc to this http://dynomotion.com/Help/StepAndDirection/StepAndDir.htm)
When I push "Move" in step response screen I see destination changing in Axis screen and bit 25 in IO screen changes state accordingly.
the step bit 24 doe not appear to change, but I suppose it is too fast for ioscreen to show the change.
 
I'll try OutPutChan=3  or is that a typo?
Would a series resistor help if it is due to input not turning off.
 
Rgds,
Tapio
 
 
 
 
----- Original Message -----
Sent: Friday, September 04, 2015 7:25 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Are you using open collector mode?  OutputChan0=3 not 11. 

Those voltages would indicate the drive is seeing:

5 - 3.6 = 1.4V

and

5 - 0.11 = 4.89V

So the drive input is probably never quite turning off. 

On the Digital I/O screen you can simulate the open state by turning off the output. The voltage should then go to about 3.85V and turn off the drive input. 

Regards
TK

On Sep 4, 2015, at 9:10 AM, 'Tapio Larikka' tapio.larikka@... [DynoMotion] <DynoMotion@yahoogroups.com> wrote:

 



Hi Tom,
 
"JP4-15&16 with voltage dividers is even less appealing" means that I tought inputs to JP4-15/16 be above 3.3V.
 
Today I tried connecting connectig +5V->drive->JP4. With IO screen I see that bits 24&25 get configured as outputs and bit 25 toggles according to direction change but I
don't get movement. I can measure 3.6/0.11 VDC between drive input(JP4 side of the input) and ground, according to the state of the output.
 
It seems that the signal is not quite strong, missing perhaps few tenths of volt.
 
Moving the wires back to FETs I again have movement.
 
Rgds,
 
Tapio
 
 
 
----- Original Message -----
Sent: Friday, September 04, 2015 9:13 AM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Sorry for the delay I missed this.

Question:  What do you mean by:  "JP4-15&16 with voltage dividers is even less appealing"

I believe that should work as an open collector drive without any problems.  Because the drive input has an LED and resistor in series it is ok to connect the + terminal to +5V and the - terminal to JP4 pins 15 or 16.

HTH
Regards
TK 




Group: DynoMotion Message: 12206 From: Tom Kerekes Date: 9/5/2015
Subject: Re: Connecting stepper motor?
Hi Tapio,

That sounds all correct.

My bad on OuputChan0=3 (that would be for JP6).

The Step bit will toggle too fast to be seen toggling on the Digital I/O Screen.  But if you continuously Jog at a high speed like 100000 steps per second then there should be a significant percentage of the time high and low and the state on Digital I/O screen should randomly toggle high and low.  

I've never heard of a case where open collector mode did not turn off the input.  But a series resistor or probably a diode in series (~0.6V drop) might be worth a try.

Take care to not have two axes configured for the same Step/Dir generator since the last power cycle.

What Version are you using?  There may have been a bug regarding muxing and open collector mode in one of the older Versions.  I just tried V4.33q and it works.

HTH
Regards
TK

Group: DynoMotion Message: 12211 From: Tapio Larikka Date: 9/6/2015
Subject: Re: Connecting stepper motor?

Hi Tom,
 
I'm using V432. I checked the changelogs and the mux bug was mentioned in 429->430.
Just to be sure that I don't have a misunderstanding:
 
Since I have movement when the step wire is toggled by FET the movement should be there by changing the wire from FET to JP4-15, presuming that muxing is OK.
I have encoders 0-6 in use. Can that have an effect?
I figured I try CW/CCW mode tomorrow.
 
Rgds,
Tapio
 
 
----- Original Message -----
Sent: Saturday, September 05, 2015 7:50 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

That sounds all correct.

My bad on OuputChan0=3 (that would be for JP6).

The Step bit will toggle too fast to be seen toggling on the Digital I/O Screen.  But if you continuously Jog at a high speed like 100000 steps per second then there should be a significant percentage of the time high and low and the state on Digital I/O screen should randomly toggle high and low.  

I've never heard of a case where open collector mode did not turn off the input.  But a series resistor or probably a diode in series (~0.6V drop) might be worth a try.

Take care to not have two axes configured for the same Step/Dir generator since the last power cycle.

What Version are you using?  There may have been a bug regarding muxing and open collector mode in one of the older Versions.  I just tried V4.33q and it works.

HTH
Regards
TK

Group: DynoMotion Message: 12213 From: Tom Kerekes Date: 9/6/2015
Subject: Re: Connecting stepper motor?
Hi Tapio,

Yes that mux/open collector bug should have been fixed by V4.32.

I assume that when using the FET you have the drive + input connected to +5V the same as with JP4-15 ?

Don't forget to try the Jog at 100000 test in the previous email.

Also try toggling IO25 from Output/Low to Input to see the voltage levels and if the drive steps (note the I/O must not have been configured for Step/Dir).

You might also try inverting the pulse with:
FPGA(STEP_PULSE_LENGTH_ADD)=63 + 0x40 + 0x80;

Sometime inputs have slower rise times than fall times soone polarity of pulse will work and the other wont.  The FET method would be much longer than the 3.78us max pulse.

HTH
Regards
TK


From: "'Tapio Larikka' tapio.larikka@... [DynoMotion]" <DynoMotion@yahoogroups.com>
To: DynoMotion@yahoogroups.com
Sent: Sunday, September 6, 2015 1:55 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tom,
 
I'm using V432. I checked the changelogs and the mux bug was mentioned in 429->430.
Just to be sure that I don't have a misunderstanding:
 
Since I have movement when the step wire is toggled by FET the movement should be there by changing the wire from FET to JP4-15, presuming that muxing is OK.
I have encoders 0-6 in use. Can that have an effect?
I figured I try CW/CCW mode tomorrow.
 
Rgds,
Tapio
 
 
----- Original Message -----
Sent: Saturday, September 05, 2015 7:50 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 
Hi Tapio,

That sounds all correct.

My bad on OuputChan0=3 (that would be for JP6).

The Step bit will toggle too fast to be seen toggling on the Digital I/O Screen.  But if you continuously Jog at a high speed like 100000 steps per second then there should be a significant percentage of the time high and low and the state on Digital I/O screen should randomly toggle high and low.  

I've never heard of a case where open collector mode did not turn off the input.  But a series resistor or probably a diode in series (~0.6V drop) might be worth a try.

Take care to not have two axes configured for the same Step/Dir generator since the last power cycle.

What Version are you using?  There may have been a bug regarding muxing and open collector mode in one of the older Versions.  I just tried V4.33q and it works.

HTH
Regards
TK

Group: DynoMotion Message: 12218 From: Tapio Larikka Date: 9/7/2015
Subject: Re: Connecting stepper motor?

Hi Tom,
 
Movement! <:-)
 
Adding a series diode did the trick!
 
As general question about steppers:
It looks like max speeds above 1200 cause the motor (without load) to loose sync: movement stops , motor loses torq and oscillates until steprate decelerates.
Drive voltage is 24VDC,  drive set to 400step/rev.
Is this normal for stepper motors?
I did know that steppers lose torq as speed rises but this was surprise to me. I expected usefull torq to 500-600rpm
 
Thank You for your help,
Tapio 
 
 
----- Original Message -----
Sent: Monday, September 07, 2015 12:31 AM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Yes that mux/open collector bug should have been fixed by V4.32.

I assume that when using the FET you have the drive + input connected to +5V the same as with JP4-15 ?

Don't forget to try the Jog at 100000 test in the previous email.

Also try toggling IO25 from Output/Low to Input to see the voltage levels and if the drive steps (note the I/O must not have been configured for Step/Dir).

You might also try inverting the pulse with:
FPGA(STEP_PULSE_LENGTH_ADD)=63 + 0x40 + 0x80;

Sometime inputs have slower rise times than fall times soone polarity of pulse will work and the other wont.  The FET method would be much longer than the 3.78us max pulse.

HTH
Regards
TK


From: "'Tapio Larikka' tapio.larikka@... [DynoMotion]" <DynoMotion@yahoogroups.com>
To: DynoMotion@yahoogroups.com
Sent: Sunday, September 6, 2015 1:55 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tom,
 
I'm using V432. I checked the changelogs and the mux bug was mentioned in 429->430.
Just to be sure that I don't have a misunderstanding:
 
Since I have movement when the step wire is toggled by FET the movement should be there by changing the wire from FET to JP4-15, presuming that muxing is OK.
I have encoders 0-6 in use. Can that have an effect?
I figured I try CW/CCW mode tomorrow.
 
Rgds,
Tapio
 
 
----- Original Message -----
Sent: Saturday, September 05, 2015 7:50 PM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 
Hi Tapio,

That sounds all correct.

My bad on OuputChan0=3 (that would be for JP6).

The Step bit will toggle too fast to be seen toggling on the Digital I/O Screen.  But if you continuously Jog at a high speed like 100000 steps per second then there should be a significant percentage of the time high and low and the state on Digital I/O screen should randomly toggle high and low.  

I've never heard of a case where open collector mode did not turn off the input.  But a series resistor or probably a diode in series (~0.6V drop) might be worth a try.

Take care to not have two axes configured for the same Step/Dir generator since the last power cycle.

What Version are you using?  There may have been a bug regarding muxing and open collector mode in one of the older Versions.  I just tried V4.33q and it works.

HTH
Regards
TK

Group: DynoMotion Message: 12219 From: Tom Kerekes Date: 9/7/2015
Subject: Re: Connecting stepper motor?
Hi Tapio,

Strange I'm not aware of another case where such a thing was required.

Many Steppers have reduced but useful torque up to 500-1000RPM

Those motors are very high resistance, voltage, and inductance motors so I would expect them to have rapid torque drop off.  Normally a supply voltage of 10-15X higher than the nominal DC coil voltage is used to be able to force current by being able to overcome the inductance and back-emf of the motor at speed.  Those are 12V motors so a 24V supply is only 2X higher.  Consider replacing the motors with something in the 2~3V range.

HTH
Regards
TK

Group: DynoMotion Message: 12235 From: Tapio Larikka Date: 9/9/2015
Subject: Re: Connecting stepper motor?

Hi Tom,
 
I chose this motor because of the very low current demand, since my 24VDC psu was already almost maxed out.
By adding separate 48VDC psu and gearing and using more microstepping I got the speed up to 6800 steps/sec which results in good enough perfomance.
 
I'm going to add an encoder tomorrow and then this assembly is close to ready.
 
Next time I know what to look for when I choose steppers.
 
Thank you again for your help
 
Rgds,
Tapio 
 
----- Original Message -----
Sent: Tuesday, September 08, 2015 3:46 AM
Subject: Re: [DynoMotion] Re: Connecting stepper motor?

 

Hi Tapio,

Strange I'm not aware of another case where such a thing was required.

Many Steppers have reduced but useful torque up to 500-1000RPM

Those motors are very high resistance, voltage, and inductance motors so I would expect them to have rapid torque drop off.  Normally a supply voltage of 10-15X higher than the nominal DC coil voltage is used to be able to force current by being able to overcome the inductance and back-emf of the motor at speed.  Those are 12V motors so a 24V supply is only 2X higher.  Consider replacing the motors with something in the 2~3V range.

HTH
Regards
TK