Hardy HI 6500 Series - Manual (Page 121)

Calibration 111
•
•
•
•
•
•
A zero reference point will vary from system to system depending on the “Dead Load” of
the vessel. “Dead Load” is the weight of the vessel and appurtenances only, with no product
loaded. In our example we will assume the dead load to be 500 pounds.
The operating range for the scale in this example is 5-10 mVDC with a 500 pound weight
range. Note that after zeroing the instrument, the 0 reading refers to the zero reference point
and not absolute 0 mVDC or absolute 0 weight.
NOTE Load cell/point measurements are checked with a digital voltmeter at the load cell
connector on the front of the module or by using INTEGRATED TECHNICIAN with a
Hardy IT Junction Box. The scale calibration must be completed to enable IT to
function correctly.
Load Check
Place a load (weight) on the scale or vessel, and check to see if the weight reading on the
input table changes in the proper direction.
For example, if the display reads 100 pounds and a 20-pound weight is placed on the vessel
or scale, the display should read 120 or some value over 100. With the display reading 100
pounds, if a 20-pound load is placed on the vessel or scale and the reading is 80 pounds, the
reading is going in the wrong direction and indicates some problem with the system.
If the display reads improperly or shows no change, something is wrong with the setup.
If the display changes weight in the proper direction, remove the weight and proceed
to calibrate the instrument. Refer to Chapter 9 on troubleshooting for additional help
to determine the cause of the poor weight reading.
C2 & eCAL Electronic Calibration
C2 or eCAL, Electronic Calibration, calibrates a scale system electronically without using
certified test weights. It can use up to 2 junction boxes with up to 4 load cells per junction
box, interconnect cable and an instrument with C2 capabilities, such as the HI 6500 series
instrument. Digital information within a Hardy C2 or eCAL-certified load sensor details its
unique performance characteristics. The HI 6500 series instrument reads the performance
characteristics of each load sensor and detects the number of load sensors in the system.
Before running C2 eCAL calibration, run all of the pre-calibration procedures. Make sure
you have configured the HI 6500 series instrument. This includes setting the units, decimal
point, NumAverages etc. For instructions please see the Chapter on Instrument
Configuration.
Gravitation Correction
Objects weigh about 0.5% less at the equator than they weigh at each pole because the force
of gravity is less at the equator than at the poles. For example an object weighing 100
pounds at the North Pole on a spring scale would weigh 99.65 pounds at the equator.