Lab5.pdf

EED4308 INDUSTRIAL AUTOMATION LAB 5 Object: Timer applications Experimental Procedure: Case I: On delay: Output B comes on at a specific set time after output A is turned on. When A is turned off, B also goes off. Question 1: For a grinding operation on a metal part, the coolent flow on the part must be on for an interval before the grinding process starts. When the process circuit is turned on, the coolent motor (CM) is turned on. Eight second later the grinding process (GM) starts. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

1 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case II: Off delay: Both A and B have been turned on at the same time. Both are in operation. When A is turned off, B remains on for a specific set time period before going off. Question 2: A motor and its lubrication pump motor are both running. Lubrication for main motor bearings is required during motor coast-down. After the main motor is shut off, the lubrication pump remains on for a time corresponding to coast-down time. In that case, a lubrication pump remains on for 20 seconds after the main system is shut down. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

2 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case III: Limited on time: A and B go on at the same time. B goes off after specific set time period, but A remains on. Question 3.1: In a sawing operation system, the sawing operation takes 4.6 seconds. After the sawing takes place, a blower to blow away the sawdust is keep running until the operation is turned off. Write a ladder program for this where both the saw, Output A, and the blower, Output B, go on at the same time. The saw, Output A, goes off after 4.6 seconds. The blower, Output B, continues to run till the system is turned by input. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

3 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Question 3.2: In a package dual stamping system operation, write a program for this where stamping times of 8 and 14 seconds are required. When the package arrives in place, a switch (Input1) is actuated and stop the conveyor. The end is stamped for 8 seconds, Output M, and the top for 14 seconds, Output N. Turning off Input 1 releases the package to continue along the conveyor. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

4 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case IV: Repeat cycling: An output pulses on and quickly off at a constant preset time interval. Question 4: In a paper mill, as finished paper comes out of a paper machine to the finished roll, a roll number is to be printed on one edge at intervals. It is determined that the number should be printed once every 12 seconds. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

5 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case V: One-shot operation: Output B goes on for a specified time after output A is turned on. Output B will run for its specified time interval even if A is turned off during the B timing interval. Question 5: An alarm is to sound for 17 seconds after a machine is started to alert personnel in the area that the machine has been started. The alarm goes on when the machine is started. The alarm stays on for 17 seconds, even if the input is turned off during the 17-second timing period. The machine could be coasting down. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

6 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case VI: Alternate on and off of two outputs: An example of this timing applications is two alternately flashing signal lights. The time on for each of the two lights may be the same’ or the two times could be set to different intervals. Question 6: There is a warning light system on a machine to indicate it is running. A single light on or a single flashing light is not deemed sufficient. Two alternating lights are required. The two lights alternate every 3 seconds. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

7 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case VII: Multiple on delay: Two different events start at different time intervals after an initial starting time reference point. Question 7: In an automation system, a metal bar is held in a fixture and shaped by three hydraulic press operations. Close Input 1 to start. Hydraulic press A presses in and stays in the pressed position. After 5 seconds, a second hydraulic press actuator B presses in from another direction and holds position. Finally after 7 seconds from the second one, a third press actuator C comes in from a third direction and holds position. Opening Input 1 release all three presses so the part may be removed. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

8 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case VIII: Multiple off delay: Two different functions remain on for two different time intervals after a process is turned off. Question 8: When the lights are turned off in a building, an exist door light is to remain on for an additional 42 seconds. In addition, the parking lot lights are to remain on for an additional 3 minutes after the door light goes out. Three outputs which are plan lights, Output A, door lights, Output B, and parking lot lights, Output C, exist in the systems. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

9 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu

Case IX: Interval time within a cycle: An output comes on 7.5 seconds after system starts up, remains on for 4.5 seconds, and then goes off and stays off. The interval would then be repeated only after the system is shut off and then turned back on. Question 9: A vacuum pump is required to be on for an interval during the process. In the system, the vacuum pump, Output A, goes on after 8.7 seconds and runs for 7.3 seconds. The overall system, Output B, continues to run after the time interval is completed. Construct the Ladder Diagram for this control system and explain the Timing Diagram of the system.

10 EED4308 Industrial Automation

Rsrch. Asst. Dr. Neslihan Avcu