CPE Installation & Commissioning Procedures 2

Question 1

What is the maximum allowed voltage drop across a PROFIBUS DP segment cable at full load?

Accepted Answer

3.0 V

Answer

The allowed voltage drop across a PROFIBUS DP segment cable must not exceed 3.0 V to ensure reliable communication.

Question 2

Which tool is commonly used during PROFIBUS commissioning to verify signal quality without disrupting live traffic?

Accepted Answer

PROFIBUS tester/analyzer

Answer

A PROFIBUS tester or analyzer can capture and decode bus traffic non-intrusively, allowing signal quality assessment during live operation.

Question 3

When installing PROFIBUS cable in a cable tray alongside power cables, what is the minimum recommended separation distance?

Accepted Answer

20 cm

Answer

A minimum separation of 20 cm between PROFIBUS cables and power cables is recommended to reduce electromagnetic interference.

Question 4

What happens if a PROFIBUS DP slave device is powered on while the master is already in Data_Exchange mode?

Accepted Answer

The slave remains in Wait_Prm state until the master re-initializes it

Answer

A newly powered slave waits in Wait_Prm state until the master sends parameterization and configuration telegrams to initialize it.

Question 5

Which PROFIBUS DP diagnostic flag indicates that a slave requires new parameterization data?

Accepted Answer

Prm_Req

Answer

The Prm_Req (parameterization request) flag in the slave diagnostic byte signals that the slave needs fresh parameterization from the master.

(CPE) Certified Profibus Engineer Practice Test