How to decide limits of balances like primary or secondary?
Minimum weight for any balance decide by its least count multiply by 10
Minimum weight of balance
When Minimum operating range shall be calculated, it should be in such a way that, the tolerance should be same or higher than the least count. For Example: For 120.0 g Balance capacity if least count is 0.001g / 1.0 mg. Then Minimum operating range is 200.0 mg, considering tolerance limit ± 0.5%. Note:-Minimum operating Limit is 200 times of least count of balance.
Maximum weight of operating range shall be calculated based 80% of balance capacity as per annexure 1. For Example : for 120 gm Balance capacity maximum capacity shall be calculated 80% of balance capacity. Then maximum capacity 96 gm,considering tolerance limit ± 0.5%.
Yes sir operating range should be 80% of its maximum capacity but minimum capacity in not necessary 200 time of least count it should be 50 to 100 time . Which may be determine by standard deviation of repeatiability
How can be define 50 or 100 time of least count please give reference of guideline
USP <41> official monograph for balance
USP General chapter 1251
Mettler Toledo GWP (Good weighing practice)
EURAMET Calibration Guide No. 18 , Version 4.0 (10/2015)
Regarding the max it is equal to the capacity as mentioned by Sartorius mechatronics document, not 80%
A simple formula for calculating minimum weight is described in USP 1251 for analytical balances
minimum weight = 2 X Standard Deviation obtained from balance calibration / weighing tolerance budget