Device &1, register &2: No transformer allocation exists

What causes this issue?

No transformer allocation exists for device &V1&, register &V2& from
&V3& to &V4&. However, the measuring type specified requires
transformer allocation.

System Response

The device allocation cannot be saved.

How to fix this error?

Enter a transformer relationship.

Procedure for System Administrators

You can turn off this check in Customizing.

Error message extract from SAP system. Copyright SAP SE.