Question 1

The IEC 61131 standard sates the five IEC 61131-3 languages. Each of the five languages provides distinct advantages so, depending upon the application, and is often advantageous to combine them. Using the internet, illustrate the distinct advantages for other four languages except IL.

Instruction List (IL)

• Text-based language similar to processor "assembly" code
• Executes the fastest of the five languages;
• Easily imported/exported

Question 2

State TWO advantages for using the subsequent bus standards in an industrial process:

       (i) Modbus-TCP

      (ii) Modbus-RTU

      (iii) DeviceNet

      (iv) Profibus

Question 3

State the commonly found components of a SCADA system.

Question 4

Explain the function of the HMI in a SCADA system.

Question 5

Modbus RTU is one of the field bus standards used in industry.

      (i)Explain with the aid of sketch the structure of the transmitted and received master/slave protocol frame.

Question 6

State one advantage of using CANopen over Modbus RTU for a field bus.

Question 7

Modbus RTU will be used with either RS232 or RS485, explain why RS485 is preferred

method of communication between a master and slaves.

Question 8

Using the internet, locate information on a safety PLC.

Illustrate the difference in concept between a standard PLC and a safety PLC.