Conversion of Orion Skyquest XX scope #poll- Motor runs no stop #poll-


Raphael T Vilardi
 

Dear All
I'm converting an existing track and go to system from OrionSkyquest XX14G to Sideral Technology. I'm using Servo Controller II, the hand pad and the ServoConfig app.

I wired the azimuth motor, motor encoder and mount encoder according to the wiring diagram. 

I disconnected the motor from the gear box so it can run freely both ways. 

When I press the hand pad, either to the left or to the right, the motor starts running full speed for 30/40 seconds until the control switches to Manual and shuts down the motor. Other ways to shut down the motor: a) turn off the Controller or b) by pressing Read Flash from the TEST AND TUNE tab. The motor would not respond to any other command from software or hand pad.
However, in some other attempts, at random, the motor runs for a short period and stops. In both cases the led blinks one second cycles
Following the Servo Config instructions, I’ve inverted the motor polarity, inverted the motor encoder and scope encoder either at the Controller and/or, by swapping the wires at the 8-way connector, re-checked the wiring with no success. The Servo Config manual says that it could also be due a faulty encoder. However, when I rewire the whole thing and return to the original system it works properly. Could it be that SciTech Controller and the motor/encoder are not compatible?
 


Don W
 

Hi Raphael,
Using ServoConfig, watch the motor encoder location and the scope encoder location to see if they are working (just press the handpad buttons for a second or so.  Be sure you have the encoder wires set to the correct servo plugs on the Servo II.  The encoders used on almost all mounts are the same optic output, so they should work.
Don W


Dan Gray
 

Hi Raphael.
I like to click on the TestAndTune button.
No uncheck both of the "Man" checkboxes.
Now there is an "Output" text box with a slider above it, there's one for the altitude just above the red "all stop" button.
the other manual slider is near the bottom center of the window.
Quickly move the slider to the center.
Now you have control of the motor by applying torque, there will be no position feedback used.
First thing on the azimuth, slowly move the slider from the center to the right.  At some point the motor will turn slowly.
Make sure with a birds eye view (assuming alt/az scope) the azimuth moves clockwise.
While it's moving, check the "Mot [            ] Loc"
This is the motor encoder location.  You should see them increasing.

Similarly, do the same thing with the altitude slider,
The scope should move up with slider motion to the right.  The "Mot[           ]Loc" should be increasing.

If the axis moves the wrong way, in the Edit Parameters, change the "Invert Motor Direction" checkbox for that axis.

Recheck the above using the "Test and Tune" again.  The motor directions should be correct.
If the motor encoder is backwards, go back to the Edit Parameters, and reverse the "Invert Motor Encoder Direction" checkbox.

Also, it's possible to have encoders mixed up between axises.  You can easily see this on the "test and tune", when you move one motor, and the other "Mot[         ]" moves, you have them reversed.

Good luck, and let us know how you fare.

Dan






On Sun, Dec 20, 2020 at 3:34 PM Don W <westergren@...> wrote:
Hi Raphael,
Using ServoConfig, watch the motor encoder location and the scope encoder location to see if they are working (just press the handpad buttons for a second or so.  Be sure you have the encoder wires set to the correct servo plugs on the Servo II.  The encoders used on almost all mounts are the same optic output, so they should work.
Don W


Raphael T Vilardi
 

Hi Dan Sorry for the delay. I had no access to the telescope until now.

Thanks for the advice. Let me try the steps right now and I'll let you know. 


Raphael T Vilardi
 

Hi Dan, I just followed the steps prescribed and yes, I got the altitude gear moving slowly clockwise and it would speed up as I moved the slider as you said it would. I had for the first time total control on speed and direction but the Mot[     ]Loc reads zero and does not change.
 
I don’t   have the full scope with me now but just the altitude system disconnected from the OTA. Could it be that I have to have both altitude and azimuth system connected to the servo controller for the thing to work?

Just for the record: I checked  the wiring over and over again both at the controller connector and at end connectors linking to the encoder terminals and scope encoders. The  5v  is there for both motor and scope encoders, and the motor encoders and scope encoders  A and B read 4.98v each.  So the energy is reaching the encoders.
 


Dan Gray
 

Did you look at the other Mot[        ]Loc in case the encoders were wired to the wrong inputs (alt to az)?
Also, do the experiment again.  WHen you have the motor moving slowly, both the A and the B should be reading average of 2.5 volts (as they go high and low).
I can't remember if you have a servoI or ||, but check the A and B right ON the connector on the controller, they should be 2.5 volts when moving slowly too.
I would be really surprised if it's the controller itself, other than lightning strikes, we've had maybe one time it was the controller, not the wiring or connector.
If it's a servoI, carefully look at the modular connector.  If a plastic separator gets bent over, it will prevent the wire contact from seating in the connector.
let us know, and merry christmas everybody!
Dan


On Wed, Dec 23, 2020 at 6:26 PM Raphael T Vilardi <rtvilardi@...> wrote:
Hi Dan, I just followed the steps prescribed and yes, I got the altitude gear moving slowly clockwise and it would speed up as I moved the slider as you said it would. I had for the first time total control on speed and direction but the Mot[     ]Loc reads zero and does not change.
 
I don’t   have the full scope with me now but just the altitude system disconnected from the OTA. Could it be that I have to have both altitude and azimuth system connected to the servo controller for the thing to work?

Just for the record: I checked  the wiring over and over again both at the controller connector and at end connectors linking to the encoder terminals and scope encoders. The  5v  is there for both motor and scope encoders, and the motor encoders and scope encoders  A and B read 4.98v each.  So the energy is reaching the encoders.
 


Raphael T Vilardi
 

Hi Dan
Merry Christmas and Happy New Year!
It is a Servo Controller II.
Reviewing your instructions: Second step:  “uncheck both of the “Man” checkboxes”. To do so one must check the “Auto” checkboxes but, if you do so the altitude and azimuth sliders stay locked. So I checked the “Man” instead.  Did I get something wrong up to this point?
After moving the altitude slider to the righ, the motor starts to run slowly clockwise. The output box reads 118, both Mot[    ]Loc reads 0. I don´t see any voltage boxes but the Amps [   ] reads 0.30.average

As I mentioned, I don´t have the full scope with me now, only the altitude set: motor, motor encoders, main gear and the scope encoders installed beneath the main gear, all these attached to one leg of the mount. Is this an issue? I  

Wiring. On the original Orion wiring: one 4-way  flat cable comes from the motor encoder and a seconf 4-way flat cable comes from another encoder linked to a smaller gear beneath the main gear which, I assume, would be scope encoder. Both 4-way flat cables connect to the Orion controller.

I measured both with a multimeter several  times: the two 4-way wires read the same: 5V, Gnd, 4.98V, 4.98V. I assume the last two to be the A & B motor encoders wires and I connected the two 4-way cables plus the motor + and – according to the Servo II wiring Diagram.

Turning on the Servo II, I measured the current, first at the Servo II  8-way  ALT/DEC connector  head screws and then at the end of the cables terminals connected to the motor encoder connectors. The reading was the same: 5V, Gnd, 4.98V, 4.98V. So, the current is flowing from the Servo II to the encoders.

What should I do now?

Best regards
 


Raphael T Vilardi
 

I've just repeated he test and measured the A and B on the connector on the controller: They read 4.98 volts, the same as when the motors are fully stoped


Don W
 

Hi Raphael,
The encoder signals must flop between near zero and +5 volts - it is a square wave signal.  Since you are always measuring near 5 volts that means your encoders are NOT sending a signal to the SiTech controller so the controller can not control the4 servo properly.

Either your wiring is incorrect or the encoders are burned out and bad.
Don W


Raphael T Vilardi
 

Hi Don  Happy Holidays!


I'm not knowledgeable in electronics, to star with, so I'm sorry if I say something silly. I rechecked the wiring.: there are two 4-way flat cables; one for the motor encoder the other for the scope encoder. The same goes for altitude and azimuth systems. I've measured the four terminals of each.  Gnd is easy to find. 5V too. The other two with 4.89V each got to be the A&B, right? The motor and scope encoders have the same arrangement. They are connected to the 8-way controller according to the wiring diagram.

There are 4 encoders. Could it be the all 4 are bad?  They were working fine with the original controller.

Should I order the encoders from Sideral Tech? I don't know whether they would fit the existing motors. I would like to order the motors too but checking their size, at 3.92 inches length it seems they wouldn't fit the existing housing and the gearbox/worm/gear without a major surgery.

 


Don W
 

Hi Raphael,

The encoders A and B voltages normally flip between 0 and 5 volts.  They are staggered, so they rarely both read 5 volts.  When they are moving, they should read about 2.5 volts (averaging the 0 to 5 volts).  Do these encoders still work with your old controller?  If they do work, then they are OK.  Since they all measure alike, I think the way you are measuring the voltages is the problem.  They are probably all OK.  You must verify the A and B wires, although it doesn't matter which is the A or B signal to SiTech.  The order of A and B can be easily reversed in ServoConfig.

You can not get new encoders from SiTech - the SiTech servos are made by Pittman company, and the encoders are built on to the servo motors.  SiTech only sells the complete servos with the encoders installed.
Don W