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AstroEQ for EQ mounts

Oily

By Oily
in DIY Astronomer

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saac

saac

Posted
Posted

Thanks Tom, that makes perfect sense.  I've held off ordering the pulleys and belts until my motors arrive and I can determine their positioning for the belt length.  Fettling up brackets at the moment.

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dolezelk

dolezelk

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I have finally assembled new motors, attaching pulleys. Works ok, kinda noisy. When tracking object at sidereal speed I see that pulley moves for half a second the stops for half of a second, and moves again for 1/2 sec, etc ... movement is kinda jumpy.  Any idea where the problem might be ? using firmware 7.3 , enabled microstepping at 1/32 rate. My mount is Skywatcher EQ5. Might be wrong motor connection ?

As a bonus I have successfully tested Bluetooth module, bypassing PIC on the board. Too bad no Adnroid app uses syntha protocol :( but PCsoftware working fine.

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Gonzo

Gonzo

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Talking about being noisy, I have an odd one. Two identical stepper motors, one is silent as it can be while the other one makes such a racket, both wired up the same way.

I even tried to swap the DEC/RA cable from the AstroEQ box with no effect, still the same motor whining....

Has anybody been in that situation, I suspect a faulty motor somehow.

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dolezelk

dolezelk

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I did try to switch motor wires but now it does not rotate at all, so I suspect wiring was ok. Going to check with oscilloscope what is going from CPU to motor driver.

I assume CPU pulls some driver signals low, to set stepping mode to 1/32 the only sets DIR and with each pulse on STEP signal motor does one step.

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TCWORLD

TCWORLD

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Talking about being noisy, I have an odd one. Two identical stepper motors, one is silent as it can be while the other one makes such a racket, both wired up the same way.

I even tried to swap the DEC/RA cable from the AstroEQ box with no effect, still the same motor whining....

Has anybody been in that situation, I suspect a faulty motor somehow.

Sounds like either a mechanical problem, or that the current limit is set either too low or too high. It's possible that the one motor requires more or less current than the other.

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Gonzo

Gonzo

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Sounds like either a mechanical problem, or that the current limit is set either too low or too high. It's possible that the one motor requires more or less current than the other.

If I put aside the possibility of an issue with the motor itself, how would one alter the current please?

found it :

First think to do is to make sure the motor cables are making good contact (the connectors on the Dual axis motors aren't great) - just try wiggling them a bit.

If that doesn't work it means the current limit to the motors is set too low. If you open up the AstroEQ box (two screws on the back), you will see two purple circuit boards. On each of these there is a small cross cut screw head which is a potentiometer. If you turn the pots about 5 degrees clockwise it will increase the current limit slightly. You can do this with AstroEQ plugged in and the motors running and that way you can see if it is having any affect.

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Gonzo

Gonzo

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I've done what you said with the potentiometer, the noise is fully gone while the motor is going back and forth. However, I had to turn it down (counter clockwise) almost to the end.

The only issue I get now is that I can hear a slight whistling noise from the motor while being stationary.

I have swapped the cable around (after shutting down the EQAstro box of course) and the noise moved to the other motor.

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Gonzo

Gonzo

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Well, here goes nothing. AstroEQ 7.3 is released. 

You can view the change log and download the new utility here:

http://www.astroeq.co.uk/downloads.php

As always, if there are any issues, let me know.

I've downloaded the latest version, unless I'm going blind, I can't seem to find the Linux tool in it.

git clone the repo and found it. thanks for the hard work.

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Gonzo

Gonzo

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Trying the new config tool under Linux, I am unable to connect to the AstroEQ.

I do have /dev/ttyS64 as ln -s

When I click on 'configure', I get 

"Read Failed!! Connection unavailable."

full error:

root@lamb:/dev# astroequploader/usr/share/doc/astroequploader/WARNING:  RXTX Version mismatch        Jar version = RXTX-2.2pre1        native lib Version = RXTX-2.2pre2[0] "/dev/ttyS64"ControlP5 0.7.5 infos, comments, questions at http://www.sojamo.de/libraries/controlP5x=0, y=154, width=516, height=372buildBeginScreen --- ID is: beginbuildVersionCheckScreen --- ID is: versionCheckbuildFirmwareFetchScreen --- ID is: firmwareFetchbuildEEPROMWriterScreen --- ID is: EEPROMWriterbuildCheckEEPROMScreen --- ID is: checkEEPROMbuildRecoverEEPROMScreen --- ID is: recoverEEPROMbuildEnterConfigScreen --- ID is: enterConfigbuildProgramConfigScreen --- ID is: programConfigbuildDownloadFirmwareScreen --- ID is: downloadFirmwarebuildTestFirmwareScreen --- ID is: testFirmwarebuildFinishedScreen --- ID is: finishedBoard Version: AstroEQV4-DIYBoard(includingKits)Matched to firmware file: AstroEQV4-DIYBoard(includingKits).hexMatched to firmware file: AstroEQV4-DIYBoard(includingKits).hexCOM Port: /dev/ttyS64/dev/ttyS64 1 :T1 :a1 :b1 :s1 :n1 :c1 :d1 :a2 :b2 :s2 :n2 :c2 :d2 :z1 :z2 1715:O11Awaiting Response...3313!Read Failed!! Connection unavailable./dev/ttyS64 1 :T1 :a1 :b1 :s1 :n1 :c1 :d1 :a2 :b2 :s2 :n2 :c2 :d2 :z1 :z2 1715:O11Awaiting Response...3313!Read Failed!! Connection unavailable.
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TCWORLD

TCWORLD

Posted
Posted

I wonder if it is because it is now using the librxtxSerial.so library from the java package rather than one packaged with it. Will have a look into that.

For Linux, if you want updates, you can add the repo to the apt source.list file:

deb https://github.com/TCWORLD/AstroEQ/raw/master/repo stable main

That way you can just do 'apt-get install astroequploader' to get any updates. You can also now run it without being in Terminal, it shows up as an application now.

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Gonzo

Gonzo

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Now my motors are no longer working correctly with the new tool config.

The RA motor is making one hell of a racket, not smooth at all, juddering.

The DEC motor is as before. DEC motor is now showing the same signs as the RA one.

Used the same settings as before, however I've picked 32 microstepping.

all fixed now, had to fiddle with the potentiometers and in the config tool I had to enter a different gear ratio.

my gears are 60-18 which would give a 3.333333333 ratio. If you enter 3.3333 for example the motors really really really don't like this.

However if you enter 3.333333333333 (12x3 after the .) then it's fine.

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saac

saac

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Looking at Gonzo's progress here has spurred me on - I'm a bit behind the drag curve.  My motors arrived on Friday and I managed to get them mounted to the mount (photo below).  So far so good, just need to measure up and order the pulleys and belts now. 

Tom, my motor data sheet shows the rated current of the motors as 2.0 A (Nema 17).  I also bought a set of the Nema 14 that you linked to at page 16 and noticed that these are rated at 1.5A.  Do you know off hand the safe current limit that the AstroEq can handle?  Would I be advised to fit a fuse to protect AstroEq?

 I bought the Nema 17 (very similar characteristics to Nema 14) because the site also provided ready made mounting brackets - if need be I can refit with the smaller motors with some minor fettling to the brackets.

Jim

http://1drv.ms/1rYO0zo

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JamesF

JamesF

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You think you're behind.  I have all the kit sorted other than the motor brackets (which won't take me more than an hour or so to make up) and it's been sitting about for months waiting for me to fit it all to my EQ3-2 so I take take that on holiday instead of my HEQ5.  A month to go and I still haven't started.  It's unlikely I'm going to find time before we leave now either.  Looks like the HEQ5 is going again :D

James

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TCWORLD

TCWORLD

Posted
Posted

2A is too much, and anything more than ~1.25A is pushing it. The driver boards will cope fine with the 1.5A motors, but you may find that you get excessive heating in the diode that protects from a reverse polarity supply being connected.

Basically when both motors are running you have to multiply the coil current by 4 to get an upper limit on the supply. I wouldn't recommend more than 5A through that diode without additional cooling/heatsink.

You will probably find that with the NEMA14 motor if you set the current limit on the driver boards to around 1.2A (the VREF pin will be at 0.6V), the motors will still provide sufficient torque to get a decent go-to speed.

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TCWORLD

TCWORLD

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I suppose you could bypass the protection diode if you felt the need, but I wouldn't recommend it - one accident connecting the supply up wrong and bang, all of the components will likely fry.

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JamesF

JamesF

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You just made my day.  I must admit I'm happy not to rush this project - I'm enjoying it too much.

There's great pleasure to be had in taking one's time to do a good job.  No point rushing for the sake of it.

James

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