Spoke with a customer seeing strange problems with this monitor. He's seeding 180 lb/ac of peas and 30 lb/ac of fertilizer on a single shoot machine. When he's seeding normally, the seed rate is approximately 675 to 700 seeds/ac. When the seed bin goes empty the seed rate jumps to 800-1000. He has 4 9AART2502 sensors, purchased in january of 2006. I didn't really have any thoughts on what's going on with this one, any suggestions?
Ryan and I believe that the product rates here are very high and probably beyond the counting ability of the sensor. So when the pea seed runs out, the system rate is higher becuase it can actually count
the individual fertilizer particles.
In simpler terms, say 1 pea seed and 2 fertilizer particles flow by the sensor as a group and get counted as 1 particle. Remove the larger pea seed and the sensor can count both fertilizer particles.
Also, because he only has 4 sensors, any small change in the particle flow will result is big changes in displayed rate. How many runs? What speed is he running at? Does the customer have the number of openers calibrated right? What SRCF?
We can calculate the seed flow in each hose (in seeds/second) with a little more information to confirm this.
180 lb/ac of peas is a big load for the fan to push. There may also be some interesting dynamics in the air system when the seed runs out causing more product to flow in the 4 hoses with sensors installed (pretty hard to prove).
I have seen the bins operate like this. The last bit drains out of the tank VERY fast. The air stream seems to move the material through faster. I do not know why; it is likely the design of the meter system. Venturi systems would be most affected.
I disagree with Ryan and Kevin that the rates are above the speed of the sensor. 180 lbs/acre of peas is not a high count rate; likewise, we can sense fertilizer rates perhaps 10 times higher.
To further investigate, we need the make/model to find out the metering system design. I very much doubt if the ART is at fault.
Not to start a debate but I dont believe Kevin clearly explained my concern with this system.
This is not a new problem from what I remeber. There have been other
reports of the same problem with large pulse seed.If it reads a lower number when both the Peas and fertilizer are double shooting then it seems that the problem is that we can not differentiate between 1 pea and 1 fertilizer at the same time or at least they are close enough together that there is not enough space between the two particles. We have seen evidence before that pulse crops double shooted do not count correctly. This has been contributed to 2 possible elements, First if there is not enough gap between the particles, Which I believe is around 1 msec, the gap will not register as a seed edge. Second is the possibility that the difference in size of the two particles can cause the software to average out the fertilizer particles because in comparison to the peas the signal swing looks like noise.