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Weigh Scale Mode

Obtaining a calibration weight:

Before the ADS1232REF can display the mass of an object, it must measure the output of the load cell for

a previously known mass. The known mass can be adjusted.

At power-up, the ADS1232REF expects a 5kg mass. If this mass is not available, or if the load cell range

is not compatible with this mass, the calibration mass can be changed in the following manner:

1. Determine the mass of the calibration weight. The most accurate way to determine the mass is to

weigh the calibration object on an accurately calibrated scale. If the weight is precalibrated, its given

mass can be used, although this approach is not generally as accurate. (Note that the accuracy of the

ADS1232REF as a scale directly depends on the accuracy to which the calibration weight can be

measured.)

2. Switch the mode switch to SCALE mode.

3. Press the PARM buttons simultaneously. The ADS1232REF enters configuration mode.

select the units used for the calibration mass. If the units shown are not correct, adjust them using the

PARM buttons.

screen, you can adjust each digit of the calibration mass separately. Select the digit using the VALUE

buttons. The currently-selected digit flashes, and can be adjusted using the PARM buttons.

6. Adjust the calibration mass to match the mass of the calibration weight.

7. Press the PARM buttons to exit the configuration mode.

Preparing Scale mode:

Do the following steps to set up the scale mode:

1. Connect the load cell.

2. If the input shorting jumpers J8 and J7 are connected, disconnect them (see Figure 1).

3. Obtain a weight of known mass.

4. If the mass of the weight is not equal to the configured calibration mass, adjust the calibration mass as

described above.

5. Move the mode switch to SCALE position. If calibration has not been performed, the display reads

NO CAL

.

6. Press the CAL button, and follow the calibration procedure given in Section 2.3.

If the calibration is performed properly, and the load cell is connected correctly, the ADS1232REF will

measure the mass of an object placed on the load cell (provided that the mass of the object is within the

device range).

Weigh scale mode is described in detail in Section 2.

2

Weigh Scale Mode

units based on the voltage received from a load cell.

The ADS1232REF operates in Scale mode when the mode switch is set to the Scale position.

To accurately calculate mass, the ADS1232REF must have calibration information for the load cell. When

calibration data when it is powered on.

By default, mass is calculated from the average of four successive readings from the ADC. The number of

points for averaging can be adjusted, and averaging can be turned off.

(1)

Load cells do not measure mass directly; they output a voltage proportional to the weight of an object. The mass of an object can be

accurately inferred from this voltage as long as a calibration is accurately performed, the downward force of gravity remains constant (as

it does if the load cell is not moved to a different altitude), and the tilt of the load cell does not change; if either of the latter conditions

change, a new calibration must be performed.

7

SBAU120B

– November 2005 – Revised July 2011

ADS1232REF User

's Guide

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