Profibus Network Architecture & Design Flashcards

What is the purpose of the Profibus DP 'Freeze' command issued by a master to a group of slaves?

Answer: Freezes slave input data until a subsequent Freeze or Unfreeze command

The Freeze command causes a group of slaves to capture and hold their current input data until the master issues another Freeze or Unfreeze command.

On a Profibus DP network operating at 1.5 Mbps, what is the maximum recommended cable segment length?

Answer: 400 m

At 1.5 Mbps, the maximum recommended segment length for Profibus DP RS-485 cabling is 400 meters.

Which Profibus DP diagnostic type is reported by a slave when a hardware fault is detected within the slave itself?

Answer: Station diagnostics

Station diagnostics (Stat_Diag) are provided by the slave to report general hardware faults or conditions that apply to the entire slave station.

In Profibus network design, what is the primary function of a bus terminator?

Answer: Prevents signal reflections at the cable ends

Bus terminators absorb the signal at each end of the Profibus cable segment to prevent reflections that could corrupt data transmission.

What Profibus DP mechanism allows a master to synchronize the outputs of multiple slaves simultaneously?

Answer: Sync command

The Sync command instructs a group of slaves to simultaneously apply their last received output data, enabling synchronized output updates across multiple slaves.

Which address is reserved and cannot be assigned to any Profibus DP master or slave station?

Answer: 127

Address 127 is the global broadcast address in Profibus DP and cannot be assigned to any individual station.

What is the key advantage of using Profibus PA over Profibus DP in process automation applications?

Answer: Intrinsic safety and power over the bus cable

Profibus PA uses IEC 61158-2 physical layer technology that provides intrinsic safety and delivers power to field devices over the same two-wire bus cable.