PERA Level 0 & 1 Technology Overview and Compromise GICSP Practice Questions (Page 6)

Questions 26–30

1. 26foundation · easy

   Which of the following protocols is commonly used for communication between Level 1 controllers and Level 0 field devices in a modern industrial network?

   • ASMTP (Simple Mail Transfer Protocol)
   • BHTTP (Hypertext Transfer Protocol)
   • CSNMP (Simple Network Management Protocol)
   • DHART (Highway Addressable Remote Transducer)
   Reveal Solution Discussion Select an answer first
2. 27foundation · easy

   Which of the following devices is considered a Level 0 component in the Purdue model?

   • AA programmable logic controller (PLC) executing ladder logic.
   • BA data historian collecting process data.
   • CA temperature transmitter that sends a 4-20 mA signal to a PLC.
   • DA human-machine interface (HMI) displaying process values.
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A manufacturing plant has a PLC that controls a hydraulic press. The press has a safety interlock that requires both hands to be on buttons to cycle. An attacker has gained access to the PLC's program and wants to disable the interlock. Which of the following is the MOST direct way?

   • AModify the PLC program to ignore the hand button inputs.
   • BPhysically short the hand button wires.
   • CReplace the PLC with a non-safety rated model.
   • DChange the HMI to remove the interlock indicator.
   Reveal Solution Discussion Select an answer first
5. 29application · medium

   A chemical plant uses a DCS to control a batch reactor. The DCS has redundant controllers. During a routine firmware update, one controller fails to reboot. Which of the following is the MOST appropriate action to maintain process control?

   • AReboot the failed controller immediately without checking the standby.
   • BSwitch control to the standby controller manually.
   • CIgnore the failure and continue with the single controller.
   • DShut down the process until the controller is fixed.
   Reveal Solution Discussion Select an answer first
6. 30application · medium

   A chemical plant uses a PLC to control a reactor temperature loop. The PLC reads a thermocouple (Level 0) and sends a 4-20 mA signal to a cooling water valve. The thermocouple is located in a thermowell. The plant has noticed that the temperature reading is slower to respond than expected. Which of the following is the most likely cause?

   • AThe thermowell is fouled, reducing heat transfer.
   • BThe thermocouple is not calibrated correctly.
   • CThe cooling water valve is not responding correctly to the control signal.
   • DThe PLC's analog input module is not configured correctly.
   Reveal Solution Discussion Select an answer first