CPE Installation & Commissioning Procedures 5

Question 1

When commissioning a PROFIBUS DP network at 1.5 Mbit/s, what is the maximum permitted segment length using Type A cable?

Accepted Answer

400 m

Answer

At 1.5 Mbit/s with Type A cable, the maximum segment length is 200 m; at 500 kbit/s it is 400 m — at 1.5 Mbit/s the answer is 200 m.

Question 2

What is the purpose of setting the 'Min_Slave_Intervall' parameter in a PROFIBUS DP master configuration?

Accepted Answer

To define the minimum time between two consecutive accesses to the same slave

Answer

Min_Slave_Intervall defines the minimum time gap between consecutive polling cycles for a single slave, ensuring the slave has enough processing time.

Question 3

During a PROFIBUS PA commissioning in a hazardous area, what parameter must be verified to ensure intrinsic safety compliance?

Accepted Answer

Maximum trunk voltage below the entity parameters (Vmax, Imax, Ci, Li)

Answer

Intrinsic safety requires that the field device entity parameters (Vmax, Imax, Ci, Li) are not exceeded by the segment power supply, as verified against the barrier/coupler specifications.

Question 4

A PROFIBUS master reports 'No_Data_Exch' for a specific slave address. After checking power and cabling, what is the next diagnostic step?

Accepted Answer

Verify the slave's bus address DIP switches or software address setting matches the master configuration

Answer

Address mismatches between the slave hardware setting and master configuration are a frequent cause of No_Data_Exch; verifying the address is the logical next step after physical checks.

Question 5

What is the role of the PROFIBUS DP Class 2 master during commissioning compared to the Class 1 master?

Accepted Answer

Class 2 provides acyclic services for parameterization and diagnostics while Class 1 runs cyclic I/O

Answer

The Class 2 master (e.g., a handheld configurator) provides acyclic access for device parameterization and extended diagnostics, while the Class 1 master handles cyclic process I/O.

(CPE) Certified Profibus Engineer Practice Test

(CPE) Certified Profibus Engineer Practice Test

CPE Installation & Commissioning Procedures 5