Loadstar Sensors DI-1000U Digital Load Cell Interface Manual - Manual (Page 15)

DI-1000 Di1000 User Guide
Page: 15 / 25
P/N : 033-01591 Rev. 6
3 C
ALIBRATING THE
DI-1000
Two calibration modes are currently supported by the DI-1000 firmware:
1. Millivolt calibration
2. 2-point linear calibration
You may perform the calibration for either mode at any time and independently select the actual
calibration mode to be used. Please ensure that the load capacity of your load cell is entered
correctly using the LC command before any calibration is performed.
3.1 Setting the calibration mode
The CAL command is used to select the calibration mode:
CAL m← selects the mV/V mode.
CAL 2← selects the 2 point calibration mode
3.2 Millivolt Calibration
Millivolt calibration is in some respects the easiest user calibration to perform. For every resistive
load cell sensor shipped, either a calibration report, or a label on the sensor itself should have the
mV/V calibration number present. This number is the best fit mV/V value determined during the
factory calibration procedure.
To enter the mVolt calibration type the following in your terminal window:
mvolt x.xxxx← (where x.xxxx represents the known mV/V calibration number for the load cell)
The DI-1000 echoed the value of the mV/V number you typed in to confirm that it has been
accepted.
The calibration value is retained until it is again changed by the user, even through DI-1000 power
cycles.
3.3 2-Point Calibration
Two point calibration can be used if you have the ability to load and unload your load cell with
known weights or forces. Two-point is the simplest form of curve fitting: a simple best fit linear
relationship between no-load, and a known load value. Accuracy will improve as the known load
moves closer to the full scale value for the attached load cell.
To begin this calibration procedure, remove any loading from the load cell. Then type the
command:
2pcal X←
(where X represents the value of the load to be used for the second point in the units set)
The DI-1000 prompts back with
Apply Point 1 Load of 0, LB Press C when ready or Q to quit
Ensure that there is no load applied to the load cell and press the “C” key. After a couple of
seconds, the DI-1000 prompts with:
Apply Point 2 Load of X, LB Press C when ready or Q to quit
Again, the “X” above represents the value of your calibration load to be applied in the units set on
the DI-
1000. Apply the calibration load to the load cell and press the “C” key.