Question 2: Answer all parts * Consider the following hydraulic shear press machine which is to be controlled by a Programmable Logic Controller (PLC), as depicted in Figure Q2. XIZM A Shear cylinder solenoid (YO) Hydraulic pump (Y1) E4 (Y2) Maintenance light Machine running light (Y3) Figure Q2 Specifically the process control actions are: Cylinder retracted limit switch (X4) Cylinder extended limit switch (X3) Start (XO) Stop (X1) a start button and a safety system OK input must both be on before the machine cycle will start. A machine running indicator light will go on to indicate machine operation. if this is the case a solenoid valve (5 port / 2 way spring returned) is activated to extend the hydraulic cylinder, provided the cylinder is in its retracted position and the hydraulic pump has been activated for at least 1 minute. the solenoid should remain active until a signal is received indicating that the cylinder is in its fully extended position - at this time the solenoid should de- activate and the cylinder should begin to retract fully. a safety check should be included, in that, if the cylinder solenoid has been on for more than 5 seconds, it suggests that the cylinder is jammed or the machine has a fault. If this is the case, the process should be shut down and a maintenanace light turned on. pressing the stop button at any time will stop the process immediately. (continued overleaf...) Inputs Required: Start button (normally open-spring returned) Stop button (normally closed-spring returned) Safety system OK (normally closed) Cylinder extended limit switch Cylinder retracted limit switch Outputs Required: Shear cylinder solenoid Hydraulic pump Maintenance light Machine running light (XO) (X1) (X2) (X3) (X4) (YO) (Y1) (Y3) (a) Implement a commented ladder logic PLC program for the control solution, indicate any internal PLC locations you may use in your solution. (20 mark (b) Explain your solution in detail. (5 mark (c) Discuss how you would implement a cycle counter, to measure the number parts produced. If the machine had a problem and had to be electrically powered down, how would you make sure that the existing cycle count is maintained prior to restarting the machine? (5 mar