Siemens SIPROTEC 5 V7.80 Operation page 85

You can also feed in the test signals using a digital test equipment. Digital test equipment offers you multiple
test programs and test sequences.
Process Mode
The process mode is the normal operation of the device.
SIPROTEC 5, Operation, Manual
C53000-G5040-C003-9, Edition 06.2018
Using On-Site Operation Panel
5.7 Displaying Device Mode
85