This rate is used to calculate an exact time period to dump the required quantity of material.
Both of these numbers are adjusted by the computer logic after each cycle as a means of continuously calibrating the dispense times.
This rate correction takes place continuously and the battery- backed RAM maintains the correct rate even when power is turned off.
If, for some reason, you were to set these numbers manually, (for example, if the load cells are damaged and you want to adjust the VOLUMETRIC flow rate), an example of a proper setting would be as follows: For a 1" auger feeder with a 60 RPM motor; this unit dispenses 8 grams per revolution which is 8 grams per second. Since the _WT gram number indicates tenths of grams (model 2xx) and the _TI number indicates interrupts (at 244 per second) then the proper numbers would be:
_WT 00080 and _TI 00244.
The computer automatically bumps both numbers up in value by doubling them both until at least one number exceeds 16,000. The ratio (rate) is still the same but error correction routines work better with higher numbers.
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_MI (set AUTOMATICALLY each time power is turned on.)
_MI numbers are set to one half the amount of material, in grams, that can feed in one second based on normal valid dispense rates. A valid rate is considered the normal dispense rate that occurs under normal conditions with equipment functioning properly. When a rate lower than half this actually occurs, it is assumed that an equipment malfunction or loss of material has occurred. Under these circumstances, normal rate correction routines are bypassed.
EXAMPLE: For a 1" auger feeder with a 60 RPM motor drive, the normal metering rate is about 8 grams per revolution or 8 grams per second. Since the _MI number is expressed as tenths of grams, (model 2xx), half of this is expressed as (_MI 00040).
It is safe to use a _MI number that is too low but NOT safe to use a number too high. Error correction routines will not work when this number is too high.
This number is reset to 00001 every time power is turned on.
After the system detects 10 good dispenses, (no retries, no bailouts), then the MI parameter is AUTOMATICALLY set to 50 percent of current flow rate. The RATE CALIBRATION routine will also set this parameter. Periodically, during production, if dispenses have occurred in a very uniform manner for an extended period of time, the MI parameter is reset based on these dispenses.
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_NC | (changes itself AUTOMATICALLY over time) |
_NC is the allowable GRAM error within which NO flow rate corrections are made by the software. Gram weight errors that are equal to, or less than, this number will be accepted and no error
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