CPE Communication Protocols & Standards 2 — Questions and Answers
Question 1: Which IEC standard formally defines PROFIBUS as an industrial communication standard?
- IEC 61158 (Correct answer)
- IEC 61784
- IEC 62443
- IEC 60870
Correct answer: IEC 61158
IEC 61158 is the international standard that formally specifies PROFIBUS fieldbus communication protocols.
Question 2: What is the maximum cable length for PROFIBUS DP at a baud rate of 9.6 kbps?
- 1200 m (Correct answer)
- 200 m
- 500 m
- 100 m
Correct answer: 1200 m
At 9.6 kbps, PROFIBUS DP allows a maximum segment length of 1200 meters per segment.
Question 3: In PROFIBUS PA, which physical layer standard is used for intrinsically safe installations?
- IEC 61158-2
- RS-485
- MBP-IS (Correct answer)
- IEEE 802.3
Correct answer: MBP-IS
MBP-IS (Manchester Coded, Bus Powered – Intrinsically Safe) is the physical layer used for PROFIBUS PA in hazardous areas.
Question 4: What token passing mechanism does PROFIBUS use among master devices?
- Token ring with logical token passing (Correct answer)
- CSMA/CD collision detection
- Polling by a central master
- Time-division multiple access
Correct answer: Token ring with logical token passing
PROFIBUS uses a logical token ring where the token is passed sequentially among active master stations to control bus access.
Question 5: Which PROFIBUS service allows a master to read and write data from a slave without a prior connection?
- Acyclic DP-V1 services (Correct answer)
- Cyclic polling (DP-V0)
- FMS services
- DPV2 isochronous mode
Correct answer: Acyclic DP-V1 services
DP-V1 acyclic services allow parameterization and diagnostic reads/writes outside the cyclic data exchange.
Question 6: What does the term 'GSD file' refer to in a PROFIBUS network?
- A device description file containing slave configuration data (Correct answer)
- A global system diagnostic log file
- A gateway station data record
- A ground shield definition for cable specs
Correct answer: A device description file containing slave configuration data
A GSD (General Station Description) file describes the capabilities and parameters of a PROFIBUS slave device for engineering tools.
Question 7: In PROFIBUS DP, which station type is responsible for performing the cyclic data exchange with slaves?
- Class 1 master (DPM1) (Correct answer)
- Class 2 master (DPM2)
- Active slave
- Passive repeater
Correct answer: Class 1 master (DPM1)
The Class 1 master (DPM1) is the primary master that cyclically exchanges I/O data with configured slave devices.
CPE Communication Protocols & Standards 2
Which IEC standard formally defines PROFIBUS as an industrial communication standard?