List two common types of PLC programming devices. Answer the following with reference to the unit process control relay ladder diagram of Figure ' 9 on page 11 : a. When do the pressure switch...

List two common types of PLC programming devices.

Answer the following with reference to the unit process control relay ladder diagram of

Figure ' 9 on page 11 :

a. When do the pressure switch contacts dose?

b. When do the temperature switch contacts dose?

c. How are the pressure and temperature switches connected with respect to each other?

d. Describe the two conditions under which the motor starter coil will become energized.

e. What is the approximate value of the voltage drop across each of the following when their

contacts are open?

(I) Pressure switch

121 Temperature switch

(l) Manual pushbutton