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TOPIC: GR-99 System

GR-99 System 12 years 3 months ago #60

  • Kendra
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Posted on google group - April 12 2006

From a Horsch GR99 System in Spain:

The customer wants to seed, no fertilizer, solid with two EMDs. The seed rate from EMD2 is reduced to zero. The motor does not turn but the system shows always Alarm "Motor 2 too slow" or "Motor 2 speed too low". Then they have reduced teh calibration to zero in teh second level - no changes. Then they have changed to GT EMDs - no changes. Is it possible that the failure is inside the Display version B?

Bill's thoughts:

From experience, I can tell you that the #2 motor has failed. It does not turn, and the display shows the right error message. The customer replaces EMD's without even trying to replace the motor, or switch the motors which would be logical. The fact that they expected setting the cal# to 0 to do something shows that they do not know what they're doing.

Another 'from experience' item: the customer complains that the motor always turns very fast, the motor RPM reports as 0. They change the EMD 20 times with no results. The Motor Tachometer is FAULTY!.

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GR-99 System 12 years 3 months ago #61

  • Kendra
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Posted on google group - April 12 2006

We have also seen motors will a partially working tachometer (we have a couple in R&D right now!). ie. The tach spits out 50 pulses instead of 100 pulses for every motor revolution. In this case, the motor is always turning twice the required RPM.

Easy way to test: Have the customer turn on the EMD cal switch, watch the meter, and time 10 revolutions. It better be 10 seconds! (60 rpm)

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GR-99 System 12 years 3 months ago #62

  • Kendra
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Posted on google group - April 12 2006

Motor alarms are generated by the EMD itself. The monitor head simply displays the alarms that the EMD tells it to.

The alarm byte in the EMD message can only be the following:
0x00 Normal Operation
0x02 Overload Condition
0x03 RPM Low Alarm
0x04 RPM High Alarm
0x05 Speed Too Slow Alarm
0x06 Speed Too Fast Alarm


NOTE: The speed too fast alarm was removed in the D2EMD (you get an RPM
Low Alarm if the actual rate falls 10% below desired rate for a min. of 4 seconds).

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