Flow Diagram 

 

Use RsLogix500 to turn the following problems into ladder programs. Record any work required to complete the problem. The completed answer should CCW file and a printed ladder diagram. Design a program to control an industrial dishwasher. The dishwasher is equipped with the following devices: ~Tank Heater N N 2 N N 2 x Float Switches (H & L) 2 x Temperature Switches (H & L) Process Pump 2 x Flow Solenoids 2 x Dosing Solenoids ~Door Switch There is a holding tank that needs to auto-regulate both level and temperature. Use a heater to control temperature and a solenoid to add water. Temperature is monitored by two temperature switches, one low and one high. The temperature should stay between these two points when the system is in "run" mode. Same goes for the liquid level via float switches. There should be a lockout on the cycle start that doesn't let the system run unless the temperature and water level are at an acceptable level. The dishwasher should start when the handle is closed and the above conditions are met. The process flow for a cycle is in the flow chart on the next page. A rinse will occur when the pump is on and solenoid 1 (1/4 " NPT) is open. The wash cycle will occur when the pump is on, either solenoid 1 or 2 are open (see next statement), and the "soap" solenoid is open; which doses the water with soap. The two options for wash cycle are "normal" and "scrubber". The normal mode will last 45 seconds and will open a /4" NPT solenoid (solenoid 1) on the outlet of the pump, the "scrubber" mode will run for 90 seconds and will open a /2" NPT solenoid (solenoid 2) on the outlet of the pump allowing for more water to flow. The sanitizer cycle will occur when the pump is on and solenoid 1 is open along with the "sanitize" solenoid; which doses the water with sanitizer. There are three options for the sanitizer cycle, 15 seconds, 30 seconds, and 90 seconds. If the door is opened at any time during the cycle, the cycle should halt and the machine return to idle. The system drains automatically. Add status logic to fulfill the feedback on the following page. Use UDFT(s) for the wash cycles. Program must include at least one seal in circuit and one latch/unlatch circuit.