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, briefly 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) Device Net

      (iv) Profibus

Question 3 :

State the commonly found components of a SCADA (Supervisory control and data acquisition) system.

Question 4 :

Decribe the function of the HMI in a SCADA system.

Question 5:

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

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

Question 6:

State one advantage of using CAN-open over Modbus RTU for a field bus.

Question 7:

Modbus RTU can 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.