Centre Pivot Position

[Christo]

Hi,

Thanks to all the guys who helped me with the 209 connection, the reason why it did not work was because the 209 was faulty. Now everything is up and running. I control my easy 721 that is 17km's away from my pc through a wireless network. All I need to do now is that I want to fit a sensor that can tell me where the centre Pivot(Irrigation system) is at any point in time. The easiest way to do this was to use a a position switch that is triggered every 10 degrees that the pivot moves throug it's circle. But the only problem with that is if the farmer moves the Pivot without the PC bieng on how will I know where it is when the pc is switched back on? I need a sensor that can tell me at any point in time where the pivot is within 10 degrees of the circle that it travels.

Anyone got any ideas?

Regards

Christo Kruger

[Mr. Spok]

Hello Christo,

do you have free inputs on your Easy? If it is, how many?

With free inputs, you can take an single-turn absolute shaft encoder with paralell-interface (it is most coding in Gray-Code or in binary-Code).

If you have 6 free inputs, you have in binary-code 64 different stats, it´s a precision of around 6 degrees.   

www.hengstler.de/gfx/file/shop/IA_ACURO_Parallel_2565064_3100107HOR.pdf

Y.S. Jan

[Christo]

Thanks for your reply Mr Spok,

Yes I still have quite a few inputs open. But as far as know those absolute encoders are very expensive? I thought of another way. I installed 32 pins in a circle around the centre pipe of the pivot and as the pivot turns a mcroswitch is triggered as it moves over each pin. I then use a retentive counter to store the position value(1 – 32) on the plc. Everything works well when the pivot is moving forward as the counter gets to 32 I reset it again to 0 and it starts counting further. My problem is when the pivot is in reverse and the counter counts down eg. 3, 2, 1, 0… then when it gets to zero it must change to 32, 31, 30, 29 eg. And I cannot get it to change to 32 from 0.

Any ideas?

Regards

Christo

[Mr. Spok]

Hello Christo,

you could order a template like in the picture around the centerpoint, with 5 microswitches on 5 inputs. You would always have the correct position at black-out of the control, too.


Jan

[Christo]

Hi Mr Spok,

That's a great idea!

Thanks

Christo

[Mr. Spok]

Hello Christo,

could you publish your programme here?

y.s. Jan

[Christo]

Hi Jan,

I found a way to use less inputs(I want to use the most cost effective plc - easy512). I use only one limit switch and two other inputs for reverse and forward. And I use two retentitive counters on the plc to store the position. So when my app starts up again it always gets the correct position from the easy. How must I post the program will must I zip it first? I see the only files that will be alowed to be added as attachments are jpg, gif, zip and pdf.

Regards

Christo Kruger

[Mr. Spok]

Hallo Christo,

yes you must first "zip" the *.e60-file.

you have two retentive counters in your programm, but what is in the case
of turning from the irrigation-machine if the power from the Easy is off??
(the counters are not working)


mfG Jan

[Christo]

Hi Jan,

No as long as the Pivot is on the Easy will also be on(they run from the same power source). What I mean is in the beginning if my app(computer program) was off it would not read the data as the pivot was turning. But now I've added two counters, so when my program starts up again it reads the position from the easy counters. I will attach the program but starngely when I switch my easy off and then on agian it does not want to go into run mode anymore. The only way to get it to go to run mode is by changing the paramaters of the 7 day time switch and after that it can be put into run mode again. Is there something wrong with my program?

Regards


Christo Kruger

[Mr. Spok]

Hi Christo,

have you set the marker in "communikation" , "systemsettings", "start run" ?
(it goes only if you online with the Easy)

Can you comment your operands in the programme? We then can understand it
better.

P.S. I have had a look at your programme, it is very confusing for me. Could you
       these declare the functional flow?

Regards Jan