An analog input module for a programmable logic controller, wherein the analog input module has a ground potential, and includes a channel output configured at a first electrical potential, a first channel input configured at a second electrical potential where the absolute value of the second electrical potential is less than the absolute value of the first electrical potential and greater than the absolute value of the ground potential. The analog input module also includes a second channel input, and a third channel input, where the ground potential of the analog input module is the ground potential of the channel output, of the first channel input, of the second channel input and of the third channel input.