juanmb
commented
2 years ago Hi Kevin. The 600 pulse encoder should work, but I never tested the software with such high resolution.
In my dome I have a three-phase motor controlled by a VFD. The Arduino is electrically isolated from the VFD with two optocouplers. In other domes I used DC motors powered by drivers like the one you have. I found that the encoder reading is much less reliable when using DC motors, because they introduce high-frequency spikes in the Arduino power line.
It is surprisingly difficult to get rid of the spurious ticks caused by the motor in the encoder. This may be the cause of your problem. You can try improving the cabling (the motor wires must not be close to the encoder wires) and adding some filtering capacitors to the lines. A better solution could be keeping the power sources isolated using optocouplers.
I don't know why the calibrate command doesn't work. Maybe the ASCOM driver sends a non implemented command. I don't currently have any Windows computer to test it.
Some time ago I started a new repository (https://github.com/juanmb/openDome) and it have a more recent version of the code, but I haven't documented it yet. It is based on Platform.io instead of the Arduino IDE.
I hope this information has been helpful.
Best regards, Juan
GoituilaHoang
Hello Juan, My name is Kevin from US. Great work on the Arduino Dome Controller! Thank you for the heavy lifting! I am having some some difficulty, and hope you can steer me in the right direction.
I have set up a new dome, and the config is as follows: Dome is Polydome. Gear reduction DC motor 27:1 coupled to spur gear 14 teeth, meshed to dome with 178 teeth. Your notes indicate an encoder on a rubber wheel reading the rotation of the dome, so I have affixed an encoder to rotate with the dome. The encoder I am using is a 600 pulse per rotation, attached to pins 2 and 3 on the arduino. The rubber wheel turns 23.1 turns with every 1 revolution of the dome. I have also affixed a Hall sensor to pin 10. I am also using buttons to move the dome manually CW and CCW to pins 11 and 12. PWM and direction is connected to a Cytron MD30 motor driver. There is no current sense. The buttons (connected to Arduino pins 11 and 12 will move the dome CW and CCW when pressed.
I am successful in connecting to the arduino in Ascom, using the MaxDome II driver, and my telescope (Meade LX200GPS). The dome will move to the home position when connected. The Maxdome Ascom driver has the option to enter the number of ticks per dome revolution (I believe that number is 23.1 x 600= 13,860.) When I set this manually in the driver and controller.ino file , the dome slews unpredictably in rotation.
The driver also has a button to calibrate the number of ticks the dome will take in one revolution: (I believe the driver counts the ticks received from the encoder in one revolution after reaching home). when I press calibrate, the dome slews to home, but when the dome should rotate, it does not, and I receive a communication 4 error instead from the Maxdome Driver. The dome stops when the magnet activates the Hall effect sensor, and the Maxdome driver reports the proper azimuth when the dome stops (0), the Maxdome Driver continues to report "Finding Home". It seems like the controller.ino file never reports "Home_Reached"
Thinking the 600 pulse per revolution encoder may be too many pulses, I also built an encoder which reads the shaft rotation of the spur gear, which should output 187 pulses for one rotation of the dome (connected to pins 2 and 3). However with 187 manually entered in the driver, the dome slews unpredictably in rotation. Pressing the button to calibrate, also gives the communication 4 error.
I have updated the dome controller.ino file "Ticks per Revolution" each time I make a correction.
I am not sure where to go from here, hoping you might have a suggestion?
Kindest Regards, Kevin