Vicpas IND110, Техническое руководство

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IND110 Technical Manual
5-2
Load cell Selection
Before any load cells are connected, determine if intended load cells will work
correctly.
1.
First identify
•
Full scale system capacity. Example: If system span is 0 -10,000 lbs, then
10,000 is the capacity.
•
Capacity of each load cell (nameplate rating)
•
Output rating of each load cell in mV/V (check nameplate)
•
Bridge resistance of each load cell (check nameplate)
2.
Calculate the parallel resistance of load cells
•
Divide bridge resistance by # of cells(Ex:4 cells 350 ohms/cell = 87.5 ohms)
(87 ohms is the lowest resistance allowed)
3.
Calculate the full scale load cell signal output
a. Mv = (system capacity) x (single cell output rating) x (excitation voltage)
(single load cell capacity) x(number of cells)
weighing range = 10,000 pounds
Single cell output rating = 2 mv/v
Single cell capacity = 5000 pounds
Number of cells = 4
Excitation voltage = 10
Mv = 10,000 lb x 2 mv/v x 10 v = 200000 = 10 mv
5000 lb x 4 cells
20000
b. The minimum full scale signal is 2 millivolts so 10 mv is acceptable.
(Another way to approximate the signal is to allow no less than 10% of the load
cell capacity for span. In the above example 10% of (4) 5000 pound cells is
2000 pounds. The above example weighing range is 10,000 pounds. It is 4
times the 2000 pounds minimum acceptable weight and is OK).