The I/O modules that are plugged onto the BaseUnits determine the potentials connected at the process terminals. The +/- potentials can optionally be identified using module-specific color-coded labels. The potentials of the AUX and add-on terminals can also be marked using color-coded labels. Advantages of the color-coded labels:

• Quick installation (one label for marking 16 terminals)
• Printed terminal numbers
• Avoidance of wiring errors
• Simple detection of potentials during servicing