LimsPulse
Analytical balance · Calibration procedure

Linearity

Weighs several calibrated weights across the range, from low to near full capacity, and checks each reading is correct.

Photo of a Analytical balance
Photo: Karelj, Public domain (cropped), via Wikimedia Commons
PURPOSE

Why this is checked

A balance adjusted at one point can still read wrongly at other loads. Linearity confirms it reads true across the whole range you use.

Frequency

Typically every 6 or 12 months, and after repair, relocation or a failed daily check, as defined in your calibration SOP.

Learn how the Analytical balance works
YOU WILL NEED

Standards & tools

  • Set of calibrated weights covering the range, e.g. 50 g, 100 g, 150 g and 200 g (OIML class E2), with certificates
BEFORE YOU START

Prerequisites

  • Balance level, clean and warmed up
  • Weights at room temperature
PROCEDURE

Step by step

  1. 1Zero the balance.
  2. 2Weigh each test weight in turn, from the smallest to the largest, placing it in the centre of the pan.
  3. 3Record each stable reading and return to zero between weights.
  4. 4Calculate the difference between each reading and the certified value.
RECORD

Example observation table

Certified value (g)Observed (g)Difference (g)% error
50.000050.0001+0.0001+0.0002%
100.0000100.0002+0.0002+0.0002%
150.0000150.0002+0.0002+0.00013%
200.0000200.0003+0.0003+0.00015%
CALCULATION

How to calculate the result

Difference = Observed − Certified value; % error = Difference ÷ Certified value × 100
  1. 150 g weight reads 150.0002 g
  2. Difference = 0.0002 g
  3. % error = 0.0002 ÷ 150 × 100 = 0.00013%
ACCEPTANCE CRITERIA

Pass if

  • Each difference within the manufacturer's linearity specification or the limit in your SOP (commonly within ±0.10% of the load, often with a tighter absolute limit).
IF IT FAILS

What to do

  • Repeat after checking the environment and the weights.
  • If it still fails, label the balance 'Out of calibration' and call service for adjustment.
  • Assess results since the last passing calibration.
MORE

Other Analytical balance calibrations

In LimsPulse · Calibration Management

LimsPulse schedules this calibration, records the result against limits, and blocks the instrument everywhere if it fails or goes overdue.

See how