CSI Installation, Configuration & Troubleshooting 4

Question 1

When commissioning an OPC UA server for plant-floor data aggregation, the integrator must configure security mode. For a production environment, which setting is required?

Accepted Answer

SignAndEncrypt – messages are signed and encrypted

Answer

Production OPC UA deployments require SignAndEncrypt mode to protect data integrity and confidentiality against network eavesdropping and tampering.

Question 2

A system integrator installs a new fieldbus segment and finds that devices randomly drop off the network. Checking the physical layer, the integrator should verify:

Accepted Answer

That the bus is properly terminated at both ends with the correct termination resistors

Answer

Missing or incorrect termination resistors cause signal reflections on fieldbus segments, leading to random communication errors and device dropouts.

Question 3

During startup of a new chiller control system, the integrator notices the supply air temperature sensor reads 15°F lower than the actual temperature. This type of error is classified as:

Accepted Answer

Offset (zero) error

Answer

A constant difference across the measurement range that shifts all readings up or down by the same amount is an offset or zero error.

Question 4

An integrator is asked to configure VLAN segmentation between IT and OT networks at a manufacturing plant. The PRIMARY reason for this segmentation is:

Accepted Answer

To reduce broadcast traffic and isolate OT systems from IT security threats

Answer

VLAN segmentation limits broadcast domains and creates a security boundary that prevents IT-side threats (ransomware, scanning) from directly reaching OT devices.

Question 5

A PLC analog output card is configured for 4–20 mA and should drive a control valve. The valve does not respond. The technician measures 0 mA at the output terminals. This most likely indicates:

Accepted Answer

The output channel is disabled in software or not enabled in the I/O configuration

Answer

A 0 mA output when 4 mA is expected usually means the channel is not enabled or is inhibited in the PLC I/O configuration, producing no drive signal.

(CSI) Certified System Integrator Practice Test

(CSI) Certified System Integrator Practice Test

CSI Installation, Configuration & Troubleshooting 4