The possible causes are:

1. In the "M" function table, in the section on customizing bits:

The number does not have 8 bits.

The number does not consist of 0’s and 1’s.

1. In the machine parameter table, an attempt has been made to assign the wrong value of bit to a parameter.

The solution for each cause is:

1. The customizing bits must consist of 8 digits of 0’s and 1’s.
2. The parameter only admits 8-bit or 16-bit numbers.