Communication Protocols & Standards Flashcards

What is the purpose of the 'Freeze' command in PROFIBUS DP?

Answer: Synchronizes input data capture across multiple slaves simultaneously

The Freeze command causes a group of slaves to simultaneously latch their input data until a new Freeze or Unfreeze command is issued.

Which baud rate is NOT supported by PROFIBUS DP?

Answer: 125 kbps

PROFIBUS DP supports 9.6 kbps through 12 Mbps but does not include 125 kbps as a standard baud rate option.

What is the maximum number of nodes (including masters and slaves) on a single PROFIBUS segment without repeaters?

Answer: 32

A single PROFIBUS segment can have up to 32 nodes; repeaters are required to extend beyond this limit.

In PROFIBUS DP-V2, what feature enables isochronous operation for motion control?

Answer: Time-synchronized cyclic data exchange with defined jitter

DP-V2 isochronous mode provides deterministic, time-synchronized data exchange with sub-millisecond jitter for coordinated motion control.

Which connector type is specified as standard for PROFIBUS DP field connections?

Answer: 9-pin D-sub (DB9)

The 9-pin D-sub (DB9) connector is the standard PROFIBUS connector defined in the EN 50170 specification for field devices.

What is the role of the bus terminator resistor network in PROFIBUS DP?

Answer: Prevents signal reflections at cable ends by matching line impedance

Termination resistors at both ends of a PROFIBUS segment match the cable's characteristic impedance (typically 150 Ω) to prevent signal reflections.

How does PROFIBUS PA differ from PROFIBUS DP in terms of physical layer power delivery?

Answer: PA delivers power to field devices over the same two-wire bus used for communication

PROFIBUS PA uses the MBP physical layer to deliver both communication signals and power to field devices on the same two-wire bus.