Eagle Microsystems EI-2000 - Manual (Page 15)

DIAGNOSTICS
The diagnostic mode is an advanced mode that one can use to restore scale calibration and
read the raw scale output in mV/V (millivolt per volt). One enters the diagnostic mode by
either the DIP switches (S1-1 & 2 = ON & S1-4=OFF) or by the front panel access method.
1.U, 2.U, 3.U, or 4.U: Scale mV/V signal
This displays the scale mV/V signal (terminals +S & -S) for each channel. The normal range
for an empty scale is from -0.1mV/V to 0.1mV/V. However, if there is a vessel, tank, etc. (with
no product) attached or sitting on the scale, this value can be higher than 0.1mV/V. The
nominal range with product on the scale is from 0.2mV/V to 3mV/V.
A DMM measuring the actual mV at the signal terminals would read about five times the
value read here (e.g., a 1mV/V “1.U” display would show as 5mV on a DMM).
DIAGNOSTIC CALIBRATION READ/ENTRY
The following parameters allow one to read and re-enter calibration zero and span. These
parameters are used for approximate calibration if one does not have test weights or the
ability to remove the weight from the scale. Entering these values, if calculated and entered
correctly, will yield a 0.25% or better calibration for each channel.
In order to use these parameters, the scale mV/V at a specific lb/kg weight (e.g., 3mV/V at
4000lbs) must be known - this is the “(scale) FULL SCALE” entry that’s written on the EI’
routing sheet.
1.o, 2.o, 3.o, & 4.o: Scale calibration dead-zero (one for each active channel)
The scale mV/V dead-zero value represents the weight of the platform and, possibly, a fixed
tank. NOTE: This value does not include the weight a removable cylinder or tank. Any
PTZ/AZ values are not added to the zero value displayed.
[FS mV/V]
DEAD ZERO = ------------------------- x [Assumed dead weight WT (lb/kg)]
[FS WT (lb/kg)]
1.c, 2.c, 3.c, & 4.c: Scale calibration span (one for each active channel)
Scale calibration value: This is the load that is typically removable that includes the weight of
the product and container combined. Use the formula below to calculate an approximate
calibration factor that’s entered into this parameter. To shift the decimal point, press the
RIGHT ARROW pushbutton on the EI-1000 or the RIGHT SELECT pushbutton on the EI-
2000.
[FS WT (lb only!)]
CAL = -------------------------
[FS mV/V]
Example: If the scale full-scale
is 3mV/V @ 4000lbs, the CAL
value entered is 1333.3.
Example: If the scale full-scale is 3mV/V @ 4000lbs and the assumed dead weight is
500lbs, the value one would enter into the dead zero value parameter is 0.3750.
Note: If the full scale weight is in kilograms (kg), multiply the weight by 2.2046 and
then divide it by the full scale mV/V value.