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Author Topic: Side Real with LV8729 driver  (Read 130 times)

kaito83

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Side Real with LV8729 driver
« on: January 22, 2021, 11:32:49 »

Dear Tom,

I recently changed to LV8729 drivers, unfortunately the bad whether I cannot test the equipment, but It's look like the sidereal is quarter of the normal.
The driver specs same as the drv8825 the 1/32 (High   Low   High) and 1/4 (Low   High   Low ).
The goto positioning is OK when I tells to the mount goes to DEC90 to 0 is fine same as RA, with hours, but I switch to sidereal it moves quarter.
example Sidereal start from 0 RA after 1 hours its reach only 0/quarter point.
I have to modify the firmware or what I'm doing wrong or is this just a mistake by myself?

Regards Tamas
« Last Edit: January 23, 2021, 22:32:52 by kaito83 »
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kaito83

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Re: Side Real with LV8729 driver
« Reply #1 on: January 22, 2021, 14:47:00 »

I Found the code
                case 32:
                    // 1/32
                    modeState[SPEEDNORM] = (( HIGH << MODE2) | ( HIGH << MODE1) | ( HIGH << MODE0));
                    // 1/4
                    modeState[SPEEDFAST] = ((  LOW << MODE2) | ( HIGH << MODE1) | (  LOW << MODE0));
                    break;

Dear Tom,

Could You fix your DRV8825 code to this
modeState[SPEEDNORM] = (( HIGH << MODE2) | ( LOW<< MODE1) | ( HIGH << MODE0));

permanently because DRV8825 is also operate in HLH in 1/32.
In the future will be compatible with LV8729 and stepper is very smooth like DC motors.

Best Regards Tamas
« Last Edit: January 23, 2021, 22:33:42 by kaito83 »
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kaito83

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Re: Side Real with LV8729 driver
« Reply #2 on: January 23, 2021, 22:24:10 »

Problem solved with the modified code, the sidereal is precise now.
And I recommend everybody the LV8729 driver and stepper motor smooth like a DC motor after this change.
I also uploaded the modified hex.
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tombkk

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Re: Side Real with LV8729 driver
« Reply #3 on: March 12, 2021, 07:46:29 »

Interesting. Is your hex code compatible with PCBv4.6 kit?  Thanks.
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TCWORLD

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Re: Side Real with LV8729 driver
« Reply #4 on: March 12, 2021, 10:05:20 »

Hi,

This change is now in the main firmware. If you use the config utility to check for updates, it will download the 8.20 firmware version which makes this change.

When configuring the AstroEQ, select the 882x driver type.

Kind Regards,
Tom
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Tom Carpenter (AstroEQ)

kaito83

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Re: Side Real with LV8729 driver
« Reply #5 on: March 12, 2021, 11:01:43 »

Thank You Tom! ;)
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kaito83

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Re: Side Real with LV8729 driver
« Reply #6 on: March 12, 2021, 11:03:20 »

Interesting. Is your hex code compatible with PCBv4.6 kit?  Thanks.

I dont know but I guess its compatible, but Tom is modified the FW now.
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tombkk

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Re: Side Real with LV8729 driver
« Reply #7 on: April 01, 2021, 11:36:11 »

Received LV8729 modules this morning. Have tried replacing 8825 modules on v4.6 AstroEQ. Here's the result:

- R.A. tracking noise is almost inaudible, so does the 8825's.
- GOTO noise is also about the same as 8825's.

Setup for both 8825 & 8729: v.8.20 F/W, CG-4 GEM, Pulley ratio 30:15 (40T pulley will hit the R.A. clutch lever) with 130-GT2 belts, 1/32 microstepping, current limit 1A, 0.9-degree/step NEMA17 motors .

Conclusion : Can't tell the difference in performance between the two modules for the above setup.

Thank you : Tamas & Tom.
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