CPE Installation & Commissioning Procedures 4

Question 1

What PROFIBUS address must never be assigned to a slave device to avoid conflict with the default master address?

Accepted Answer

1

Answer

Address 1 is typically reserved as the default programming device (class 2 master) address, so it should not be assigned to slave devices.

Question 2

During spur installation on a PROFIBUS PA segment, what is the maximum allowed spur length to avoid signal reflections?

Accepted Answer

30 m

Answer

On PROFIBUS PA segments, individual spur lengths must not exceed 30 m (in non-intrinsically safe installations) to avoid signal reflections that corrupt communications.

Question 3

What is the correct procedure when replacing a failed PROFIBUS DP slave with a unit that has a different hardware revision?

Accepted Answer

Update the GSD file in the master configuration and re-download if the I/O map changed

Answer

If the hardware revision changes the module configuration or I/O layout, the master configuration must be updated with the correct GSD file and re-downloaded.

Question 4

Which commissioning step verifies that all PROFIBUS slaves are correctly identified before enabling process control?

Accepted Answer

Comparing the projected slave list with the live diagnostic scan

Answer

Comparing the engineering tool's projected slave list against the live bus scan confirms every expected device is present and responding before process startup.

Question 5

What is the significance of the 'Ident_Number' field in a PROFIBUS GSD file during commissioning?

Accepted Answer

It uniquely identifies the device type so the master can verify it is communicating with the correct device

Answer

The Ident_Number is a unique manufacturer-assigned identifier; the master compares it against the slave's reported ID to confirm device type compatibility.

(CPE) Certified Profibus Engineer Practice Test

(CPE) Certified Profibus Engineer Practice Test

CPE Installation & Commissioning Procedures 4