Near Intersection of I-35 & I-90 Southern Mn. | As I'm certain you are aware, the speed and thus the rate of your fertilizer pump is controlled by PWM (Pulse Width Modulation). For those who may be interested, the process works as follows.
Pulse Width Modulation is a common approach used to change the speed of a DC motor, the output of a hydraulic valve or the "brightness" of LED lights among other things. The idea is that the system sends out short "shots" of 12V rather than a reduced voltage. The device such as a DC motor, hydraulic valve or lights then behave as if they were fed with a lower average voltage.
In the past this was usually done with a Rheostat which really just reduced the voltage by turning it into heat. The PWM concept is much more efficient and controllable.
The Ag Leader Liquid Product Control Module can be programmed to behave as a PWM controller. When the calculated applied rate is different than the target rate entered by the operator, the system changes the "width" of the short shots of 12V in an attempt to speed up or slow down the pump and thus bring the applied rate in close agreement with the target rate.
The problem is that the Liquid Module cannot handle electrical loads over 1 amp. It could run a small DC motor, a hydraulic valve or some lights but the electrical load of the fertilizer pump is just too great.
The common solution is to add a DC motor driver. The DC motor driver is an electronic "box" that goes in between the Liquid Product Module and the fertilizer pump. The DC motor driver has a pair of heavy leads that connect directly to the vehicle battery. It has a pair of rather heavy output leads that go to the DC motor. It has a pair of light duty wires that are attached to the output of the Liquid Module.
In operation, the Liquid Product Control Module produces the PWM pulses that it feels are appropriate. The DC Motor driver creates a high current version of these pulses that mimic the duration and is what actually runs the fertilizer pump. Thus the relatively heavy load of the pump is carried by the battery. The module is spared the extra load.
From you description, it doesn't sound good for the DC motor driver. I'm quite certain you have checked the high current connections directly to the battery but with no indication on any of the LEDs it doesn't look good for the module. I suppose it could have caused the blackout of the InCommand. My advice would be to check all the connections which should be going directly to the battery. If a battery disconnect switch is involved this could add confusion to the situation.
Considering the motor driver was used, that would lead to some suspicion about it. |
Bad dc motor driver?
