DiSEqC motor is not moving properly

[mohanaprakash]

Hi

I am having a SG2100 DiSEqC motor, in my set top box there is a option called recalculate position, which will recalculate all the stored position. sometimes this command is not working properly.

I did the below tests, i stored following dish positions in location 1,2,3,4 respectively.

Store position Dish position
1 10 W
2 20 W
3 30 W
4 40 W

Test 1
After this i moved my motor to 5W and pressed the recalculate position, now i command motor to move position 2, then it stops at 15W as i expected.

Test 2
After this i moved my motor to 5W and pressed the recalculate position, i moved my motor to reference position, now i command motor to move position 2, then it again going to 20W. It is not recalculated, every time when i do this test behavior is same.


If any have any input why my motor is not working properly.

regards
mohanaprakash

 

[turbosat]

I thought that recalculate only worked if the dish had at least one satellite position properly stored (and was on that position when "recalculate" is commanded).
Maybe I'm wrong-never tried it.

 

[mohanaprakash]

Hi

after i stored the position, i checked whether all positions are stored properly or not. Positions are stored properly. after i did Test 2, but the result is same .

 

[turbosat]

Perhaps the motor has to be at the zero position for that to work, again I have never tried.
USALS documentation may explain it fully.

 

[mohanaprakash]

Hi checked in USALS standards, this is the input they are providing, but it is not answering me. If you have any idea please help me out.

“(Re-) Calculate Satellite Positions”

Command byte ‘6F’ with various data parameters can give the user/installer
various types of “short-cut” to setting up or aligning the system. The basic
command has the (first) parameter byte set to zero, i.e. command ‘6F 00’
which can initiate any appropriate function, defined by the manufacturer of
the Positioner Motor Unit. In general, the user/installer will manually drive
the antenna to receive a strong signal from a suitable satellite and then the
command ‘6F 00 {00 00}’ will cause the embedded software in the Positioner
Motor Unit to calculate the (approximate) positions of all the other satellites
in its memory (ROM) relative to the known position. The user/installer may
then need to optimise each position in turn with reference to the received
signal strength.
It is preferred that Tuner-receiver/IRDs with Menu systems should support 3
(signed) binary parameter bytes for the “Calculate Satellite Positions”
command. Again, their exact function will be defined in the documentation
for the Positioner Motor Unit, but they typically may be used for, “Satellite
Number”, “X-Value” (e.g. Site Longitude in degrees) and “Y-Value” (e.g.
Site Latitude in degrees). Thus if the user/installer can receive any
(identifiable) satellite signal, then the command can contain sufficient data to
calculate the positions of all other satellites stored in the Positioner Motor
Unit’s ROM.

Strictly, the “X-Value” data byte cannot define a unique Longitude in the
World because its range is only 256 degrees. However, a suitable range can
be inferred from the range of satellites for which data is stored (i.e. those
expected to be above the horizon in the relevant continental region). In
Europe and Africa the “X-Value” can be signed binary (positive to the East)
so that it defines longitudes from 128° West to 127° East. In the Middle East
and Asia the “X-Value” can be unsigned binary so that it defines longitudes
from 0° to 255° East (i.e. to 105° West). In the Americas the “X-Value”
generally would be unsigned binary to the West, so that it defines longitudes
from 0° to 255° West (i.e. to 105° East).

Reference : EUTELSAT POSITIONER APPLICATION NOTE - VERSION 1.0

 

[turbosat]

Sorry , all that is way over my head, lol. I was just making some guesses, sometimes I get lucky.
Maybe somebody else who understands that motor-protocol stuff better than I do will help you out.

 

[DishDigger]

I'm like Turbosat, this is pretty much over my head, but I'll try to make a stab to help. Maybe with a little experimentation you can find out if I'm even close.

You'll note in the second paragraph of your posting on the recalculate description it says:

"Thus if the user/installer can receive any (identifiable) satellite signal, then the command can contain sufficient data to calculate the positions of all other satellites stored in the Positioner Motor Unit’s ROM."

What I did with my SG380 when I was trying to get it to find sats, I got 91W programmed in and tried to move to 123W, but couldn't get anything to happen. I used the buttons on the bottom of the motor to "sweep" to 123W and when I got it centered, I hit "recalculate" and then it would track the other sats that were listed in the receiver (and consequently in the newer positioner or motor).

The motor won't "invent" positions, it will go to the ones that are programmed in the ROM. Your manual should list the programmed positions in the unit.

Hope this is of help.

Bill

 

[mohanaprakash]

Hi thanks for your input.

But i found one thing when i was testing yesterday, After i recalculate the positions, if i stored the positions manually, then all recalculated positions were remain in the ROM, otherwise it is not stored. Similar is the case with goto reference also.

 

[ELMWOOD]

Why are you beating yourself up with this? Zero the motor. With mount brackets slightly loose move the entire motor and dish to your true south sat. Tighten all mount bolts and you are now on the arc.