LOAD CELLS OVER ANALOG LOAD CELLS

POINTS

DIGITAL LOAD CELL

ANALOG LOAD CELL

Accuracy

Each DLC has an individual A/D converter. This helps in generating higher internal counts for the total system and hence a lower division size can be achieved leading to higher accuracy.

Signals of all 4/6/8 load cell are shorted and connected to a single A/D converter in the indicator. This leads to a smaller number of internal counts from the ADC which leads to a high value of division size and hence lesser accuracy.

Electrical Noise

ADC and micro controller are built in the load cell & the output is serial digital signal. There is no effect of electrical noise even if the load cell cable is long or the environment is electrically noisy.

Output of combined analog load cell is from 0.1 µv to 3 µv per unit load. This is a very small and sensitive signal which is sensitive to any electrical noise present around the cable and indicator and may lead to unstable weight display if the cable length is long or the environment is electrically noisy.

Calibration

Are pre calibrated with weight and hence no calibration is required in the field. Only a small corrective calibration may be required if there is major structure deformity.

Calibration has to be done in the field using test weights. This is a very expensive and cumbersome process.

No Corner Error

As every load is pre-calibrated in the factory, there is no corner error during installation or even with regular usage.

Corner has to be tested and removed manually which is a very tedious and expensive process. If corner errors are generated during regular usage, it is very difficult to find and remove these as it will require operator and engineer skills.

Replacement

Since the DLC are pre-calibrated in the factory, it can be easily replaced in the field without the hassle of scale calibration or corner error removal. Even if a different capacity load cell is used for replacement, the result is the same.

If any ALC is replaced in the field, it will require scale calibration with weights and also corner error removal. This is because the load cells have variation in their analog outputs which has to be matched with the other load cells used in the scale.

Distance between load cell & indicator

As the output signal is digital, the distance between load cells & indicator can be as long as 500m without use of signal repeaters.

As the output is analog with values in micro volt, the same is very sensitive to electrical noise pick-ups. Under this circumstance, the distance between load cells and indicator is limited to 20 meters.