Troubleshooting & Maintenance Techniques Flashcards
7 cards from real CPE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Troubleshooting & Maintenance Techniques flashcards as text
A repeater is used in a PROFIBUS DP network. Which statement about repeater placement is correct?
Answer: A repeater counts as one device on each of the two segments it connects
A PROFIBUS repeater occupies one device address on each segment it bridges, so each segment can have a maximum of 31 field devices plus the repeater (32 total).
When replacing a PROFIBUS slave device in a live plant, which precaution is MOST important to ensure minimal disruption?
Answer: Ensure the replacement device has the same PROFIBUS address and GSD parameters as the original
The replacement device must have the identical PROFIBUS node address and compatible GSD configuration so the master can automatically re-establish communication.
What diagnostic information is contained in the 'Manufacturer Specific Diagnostic' portion of a PROFIBUS slave's diagnostic response?
Answer: Device-specific fault codes, status information, and operational data defined by the device manufacturer
The manufacturer-specific diagnostic area allows vendors to include device-specific information such as sensor faults, calibration status, and internal error codes beyond the standard PROFIBUS diagnostic bytes.
A PROFIBUS network exhibits intermittent errors that are correlated with operation of nearby variable frequency drives (VFDs). The MOST effective solution is:
Answer: Install ferrite cores on PROFIBUS cables and verify proper cable shielding and grounding
Ferrite cores attenuate high-frequency EMI from VFDs, and proper shielding/grounding prevents inductive and capacitive coupling of noise onto the bus.
Which parameter in the PROFIBUS DP master configuration defines how long the master waits for a slave's response before declaring a communication error?
Answer: Tslot (slot time)
Tslot (slot time) defines the maximum time the master waits for a slave response token; if no response arrives within this window, a communication error is flagged.
During PROFIBUS maintenance, you discover a connector with bent pins on the RS-485 port. Before replacing the connector, which measurement should be taken?
Answer: Measure the differential voltage between A and B lines to assess signal quality
Measuring the differential voltage between A and B lines confirms whether the electrical connection is still functional and reveals the extent of signal degradation.
A PROFIBUS DP system is configured with a Data_Control_Time of 5 ms. This parameter primarily affects:
Answer: How often the master sends global control commands
The Data_Control_Time defines the interval at which the master sends Global Control commands (such as Sync and Freeze) to control groups of slaves.