18.1 Description

Helios uses a 4-channel D/A converter (DAC) to provide four analog voltage outputs. The standard configuration uses a 12-bit DAC, however a 16-bit DAC is available as a special ordering option. A 12-bit DAC can generate output voltages with the precision of a 12-bit binary number. The maximum value of a 12-bit binary number is 212 - 1, or 4095, so the full range of numerical values that the DAC supports is 0 - 4095. The value 0 always corresponds to the lowest voltage in the output range, and the value 4095 always corresponds to the highest voltage minus 1 LSB. The theoretical top end of the range corresponds to an output code of 4096 which is impossible to achieve with a 12-bit number.