When describing the contacts of a KIO module, the terms "potential-free" and "potential-loaded" appear. Disregarding them and connecting them incorrectly may lead to errors during operation or may destroy the device. In the following the terms are defined.

  • Potential-free means that a connection is passive, i.e. it does not or must not supply voltage itself.
  • Potential-loaded means that a connection is active, i.e. it supplies or must supply a voltage itself.

When connecting interfaces, a potential-free contact is usually always connected to a potential-loaded contact, i.e. one side is voltage-free, the other side is voltage-loaded.

If both sides are potential-free, the communication does not work. If, on the other hand, both sides are potential-loaded, in the worst case the device may be destroyed.


The I/O module 7017 has no potential-free or potential-loaded inputs. It has 8 analog inputs for measured values (0-10 V, 4-20 mA)


The I/O module 7052 has 8 digital inputs for circuits with potential.


The I/O module 7053 has 16 digital inputs for potential-free circuits.

You can find further information here Kentix IO-Modules