CPE Electromagnetic Compatibility (EMC) & Physical Layer

Question 1

What is the characteristic impedance of Profibus Type A cable as specified in EN 50170?

Accepted Answer

135 Ω

Answer

75 Ω

Answer

100 Ω

Answer

150 Ω

Question 2

What is the minimum differential input voltage that an RS-485 receiver used in Profibus must recognize as a valid signal?

Accepted Answer

200 mV (0.2 V)

Answer

500 mV (0.5 V)

Answer

1.0 V

Answer

1.5 V

Question 3

Which grounding practice is recommended for Profibus cable shields to prevent ground loop interference?

Accepted Answer

Single-point grounding at one end only

Answer

Ground at both ends

Answer

Leave the shield floating

Answer

Ground at every junction box

Question 4

What is the maximum allowed segment cable length for Profibus DP operating at 12 Mbit/s?

Accepted Answer

100 m

Answer

200 m

Answer

400 m

Answer

1200 m

Question 5

Which passive component is commonly integrated into Profibus bus connectors to suppress high-frequency common-mode noise?

Accepted Answer

Ferrite bead

Answer

Electrolytic capacitor

Answer

Metal oxide varistor

Answer

Zener diode

Question 6

At what angle should Profibus signal cables cross AC power cables to minimize electromagnetic coupling?

Accepted Answer

90° (perpendicular)

Answer

0° (parallel routing)

Answer

30°

Answer

45°

Question 7

What is the maximum capacitance per unit length permitted for Profibus Type A cable?

Accepted Answer

30 pF/m

Answer

10 pF/m

Answer

60 pF/m

Answer

100 pF/m