BL4: Refl. on Control Design, Safety &Monitoring Sys. (5.3&5.4)

Process safety relies on the principle of multiple protection layers (AIChE, 1993b;ISA, 1996). Which of the protection layer is in the correct sequence of activation when a plant incident happen?

• Process design, SIS, BCPS, Critical Alarm, Physical protection, Emergency response
• Process design, BCPS, Critical alarm, SIS, Physical protection, Emergency response
• Process design, BCPS, Physical protection, SIS, Emergency response
• Process design, Physical protection, SIS, BCPS, Criitical, Emergency response

Process alarms is used to call attention to abnormal situation. An alarm continues until it is acknowledged by an operator action such as pressing the button/ key in a computer keyboard

• TRUE
• FALSE

Which of the following is not true regarding on the good control practice for plant safety?

• Never disable of SIS
• Use independent equipment for each safety layer
• Use the same sensor for control, alarm and SIS
• Test safety system on regular basis

Programmable logic controllers (PLCs) is a specialized computer that connected to a set of input/output (I/O) devices with the programmable memory that store instruction and specific function in controlling process and machines.Which of the following statement is true

• The computers are programmed to respond to inputs by sending outputs to maintain all processes at setpoint
• Input from sensing devices is transfer to the input module before processing in the CPU unit. It is then transferred to the output module before receiving by the output device
• A sensor is connected to the input PLC while an actuator is connected to the output PLC
• the CPU monitors the inputs and makes decisions based on instructions held in the program memory.
• All above

Which of the following statement for the three major types of PLC applications is not true?

• A single ended application involves one PLC controlling one process
• A multitask PLC application involves multiple PLC controlling several processes
• A control management PLC application involves one PLC controlling several others PLC

(a)   is connected to PLC output. It is used to convert an electrical signal from the PLC into a physical condition.

A distributed control system (DCS) refers to a control system (manufacturing system, process or any kind of dynamic system) of sensors, controllers, and associated computers that are distributed throughout a plant. Which of the following statement is not true regarding on DCS?

• makes automated decisions based on production trends it sees them in real-time throughout a plant.
• Used to control complex, large and geographically distributed applications in industrial processes
• The distributed controllers are connected to both field devices and operating PCs through low speed communication networks
• Controllers are distributed geographically in various section of control area and are connected to operating and engineering stations

SCADA is system and technology for remote monitoring and control, which allows the operator to get data, exchanging data, displaying and supervise process. Which of the following sequeces on the basic operation is true?

• Data acquisition, network communication, HMI (human machine interface), MTU (Master terminal unit)
• network communication, Data acquisition, HMI (human machine interface), MTU (Master terminal unit)
• Data acquisition, network communication,MTU (Master terminal unit), HMI
• Option 4

Which of the following disadvantages of SCADA is Not True?

• The system is more complicated.

• Different operating skills are required, such as system analysts and programmer

• a lot of wire to deal

• The data can be viewed just on site

DCS is process oriented, whereas SCADA focuses more on the acquisition and data collation of data. Both of the system similar in term of its hardware and components.

• True
• False