In the equivalent weight system most manufacturers set their minimum weight at T1 as only 2.5% of samples can legally be below T1. (No samples can be below T2. Working out T2 is very simple as this is double the difference between Target Weight and T1 weight).

There are eight different ways to work out T1 from the Target weight and the method used is determined by between which range the Target Weight falls. The T1 calculator automatically determines between which range the Target Weight falls; hence always calculates the correct value of T1. Hence there is no need to memorise the ranges or consult a table. Where a T1 value cannot be calculated, because the Target Weight is too low, a ‘Weight is out of range’, message is displayed.

When the T1 calculator is first ran it prompts the user to enter the Target Weight in grams and displays where T1 will be displayed in grams. Once a target weight has been entered the Calculate T1 button is pressed to obtain the appropriate T1 value is displayed.

The TI Calculator provides the user with two options:

The first option is to use complete numbers or integers. This is the default option, when this calculator is first loaded.

The second option is to use one decimal place. To choose this option, press the Decimal Point toggle button, so that it turns blue. To revert back to an integer, press the Decimal Point toggle button again. This button is then shaded grey.

In line with the three packer’s rules, where the integer option is chosen the calculator automatically rounds up to the nearest gram, where applicable and where the one decimal place option is chosen the calculator automatically rounds up to the nearest tenth of a gram, where applicable.

If the Target Weight is changed, the value for T1 automatically clears so no false readings are made.

T2 is also calculated if required. T2 is always twice the difference from the Target Weight to T1. For example if the Target Weight is 1000g; T1 will be 985g. The difference is 1000- 985 = 15g. Hence twice the difference is 30g so T2 will be 970g.

To show T2 press the T2 Toggle button. The default is that the button is off so T2 is not displayed. This is to prevent using T2 as the minimum weight instead of T1, A further safety precaution is that the T2 display is often under the number pad, so the number pad needs to be hidden to show T2. This is usual done by pressing the down chevron on the number keypad.

T2 is displayed the same way as T1 as far as the decimal place. If the Decimal Point toggle button is selected (that is displayed blue), one decimal place is shown on the T2 display; otherwise no decimal places are shown. The value of T2 is automatically rounded to the nearest number of one decimal place in line with the three packers rules.