I have started noticing that there is a lot of confusion about adjustments of swath control settings on the Greenstar displays. For simplicity sake I’m going to discuss planters, but the principals here should be used across all platforms. A lot of people are changing the turn ON/OFF time to adjust where their seed placement is. This is wrong for a couple of reasons.
Turn ON/OFF times should be a static number. They should represent the total amount of time that it takes once you send the command to turn on or off and you see seed drop/stop. Or on a sprayer from the time that you turn on the master till the spray has reached full pattern and when you turn off that the check valves have closed. If the times are correct you should be able to come across a previously covered spot at any speed and have it shut off appropriately. On a planter with row-command it happens so fast that it is very hard to measure. The typical turn on time is .9 sec and the typical turn off time is .3 sec for that setup.
If you are adjusting the times from those measured to fix your seed placement you are masking another problem. Most likely your measurements are not correct. An incorrect measurement will not properly tell the display where the actual swath control location is at and therefore could be sending the signal to start/stop at the wrong time. Giving you the feeling that your turn ON/OFF times are incorrect.
First thing you’ll want to do is make sure that all of your machine and implement offsets are correct. The display will put default values in whenever you setup a machine and implement. Most likely these are a few inches off.
On the machine offsets, an example of a variable that can occur is whether you are using an original shroud or the new deluxe shroud for your receiver. This will change the “B” value on the machine offsets page.
The “C” value on machine offsets is going to be different whether you are pulling a drawbar planter or a 2pt hookup planter. You need to make sure that you have the correct connection type selected on your machine setup page. Either “Rear Drawbar” or “Rear Pivot 2pt”. If you are using a “Rear Drawbar” you will measure from the rear axle to the hitch pin. On a “Rear Pivot 2pt” you will measure from the rear axle to the pivot pin on the planter tongue. Make sure that you measure that with the 2pt hitch in the planting position and not the transport.
When setting up your implement offsets you will notice a little reminder in red letters. It says that “A + B equals swath control location”. What this means is that whatever your “A” and “B” values, when added up, is where the display is expecting the location of whatever application you are doing. So in planting this is where the seed hits the ground, or the bottom of the seed tube.
The planter measurements will most likely be wrong. The “A” value will be very close. It is measured to the front of the frame. In all the ones I have measured I get within a tenth of an inch, but still make sure to measure it. Measure from the pivot pin/drawbar pin (depending on planter type) to the front of the frame.
The “B” value will be measured from the front of the frame to the bottom of the seed tube. Usually the default value that the display puts in for planters is way off. Since on most Deere planters the middle 4 rows are further back than the rest of the rows you will need to decide where to measure to. My personal preference is to go to the closest rows since there are more of them. I’m more about saving the seed and money than over planting 20 rows for 4 rows. Usually you’ll have it going close enough to the row that you will hardly notice those 4 rear rows.
Now I know measuring the times for a planter is a pain, but there is a way to figure it out. If you were diligent in your measurements and you know they are right, you can now fine tune your “turn ON/OFF” times. First you need to go into your swath settings and make sure on the coverage box that it is set to “% Overlap” and the box says 100%. It might only take moving it a 1/10 sec. at a time, but you can dig and see whether you are getting too much overlap or a skip. Technically the swath control should be shutting it off half the width of your rows. So a 30″ row should be shutting off 15″ before the row.
With the proper times and measurements in you should be able to come in and out of the headland at any speed and have it shut off and turn on in the same spot. If you have the wrong measurements in and you used the “turn ON/OFF” times to adjust seed placement, when you come across at different speeds you will find that the seed placement will not be consistent and will not give you satisfactory results.
After you you get the times and measurements right, you can control overlap and skip by adjusting the coverage box in swath control settings. The “% Overlap” will go from 0% to 125%. With the 125% you will achieve some overlap if that is what you desire.
I know this is more Deere oriented, but the principals here can be applied to most other systems. They would all have adjustments similar to this.
UPDATE: I had a fellow AMS consultant bring up a point that I forgot to mention here that is also important to proper operation. When coming in and out of headlands you want your speed to remain as constant as possible. What this means is that you do not want to slow down or speed up within feet of your coverage line. A quick math example will show this.
If your speed is 5 MPH your are moving 7.3 ft/sec. If your turn on time is 1.0 second, that means swath control will send the command to turn on 7.3ft in front of your coverage. If within that 7.3 ft you speed up to 6mph you are now moving 8.8 ft/sec. You will have added a 1.5 ft gap to your turn on, therefore leaving a skip.
No matter what speed you come across the line at, you want to be consistent. If your times and measurements are right it won’t matter if you come across at 2 mph or 5 mph, but it will matter if you don’t remain at a constant speed going across the line. Don’t slow down or speed up right at the line and this will help improve your satisfaction with swath control. I tell people once your tractor hits the coverage line to not make any adjustments to speed until the implement is across the line and the display shows that your swath control has shut off or turned on properly.
Another thing along this note is make sure you have the implement down plenty of time before the line so that the swath control has time to send the command and execute.