LogixPro Door Opener Exercise 4; halt door using Open or Close PB. LogixPro DUALCOMPRESSOREX4.rsl. Traffic light ex 3 solution.rsl Delay red light 1 sec 22. Traffictimerseq.rsl Traffic using Sequence 19402. LogixPro Dual Compressor Exercise - TheLearningPit Combine our ProSim-II programmable process simulations with a PLC Editor/Emulator which mimics Allen-Bradley's (Rockwell) RSLogix 500, and you have LogixPro 500; a complete stand-alone PLC training system without the expense of a PLC. Solution LogixPro Bottle Line Exercise 1&2 The LogixPro Student Resources and Programming Exercises are designed to aid the student in mastering the fundamentals of RSLogix operations, programming and troubleshooting using TheLearningPit's LogixPro PLC simulation software. Traffic light ex 3 solution.rsl Delay red light 1 sec 18. Traffic light 2.rsl LogixPro Traffic Light Simulation using 4 timers. Bottle Fill Exercise 5, LogixPro Simulator 19103. LogixPro BATCHSIMULATOREXA2.rsl. From the LogixPro Simulations Menu, select the I/O Simulation. Clear out any existing program by selecting the 'New' entry in the File menu, and then select the 'Clear Data Table' entry in the Simulations menu. Now enter the following program being careful to enter the addresses exactly as shown.
The CTU and RES ...... Counter Instructions
Initial State (Switch I:1/0=Open):
C5:1.ACC = _______ C5:1.PRE = _______ C5:1/CU = ___ C5:1/CD = ___ C5:1/DN = ___
Final State (Switch I:1/0=Closed):
C5:1.ACC = _______ C5:1.PRE = _______ C5:1/CU = ___ C5:1/CD = ___ C5:1/DN = ___
Conclusions:
The CTU output instruction counts up for each false-to-true transition of conditions preceding it in the rung and produces an output (DN) when the accumulated value reaches the preset value. Rung transitions might be triggered by a limit switch or by parts traveling past a detector etc.
The ability of the counter to detect a false-to-true transitions depends on the speed (frequency) of the incoming signal. The on and off duration of an incoming signal must not be faster than the scan time.
Each count (accumulator) is retained when the rung conditions again become false, permitting counting to continue beyond the preset value. This way you can base an output on the preset but continue counting to keep track of inventory/parts, etc.
Use a RES (reset) instruction with the same address as the counter, or another instruction in your program to overwrite the value of the accumulator and control bits. The on or off status of counter done, overflow, and underflow bits is retentive. The accumulated value and control bits are reset when a RES is enabled.
The CTD ...... Count Down Instruction
Conclusions:
The CTD output instruction counts down for each false-to-true transition of conditions preceding it in the rung and produces an output when the accumulated value reaches the preset value. Rung transitions might be triggered by a limit switch or by parts traveling past a detector.
Each count is retained when the rung conditions again become false. The count is retained until a RES (reset) instruction with the same address as the counter is enabled, or if another instruction in your program overwrites the value.
The accumulated value is retained after the CTU or CTD instruction goes false, and when power is removed from and then restored to the processor. Also, the on or off status of counter done, overflow, and underflow bits is retentive. The accumulated value and control bits are reset when a RES is enabled.
Applying Counter Instructions .... An Up/Down Sequence Example
Conclusions:
The CTU is by far the most commonly used counter instruction. It can, and is utilized in almost a limitless number of counting applications, and is typically very easy to understand and employ.
The CTD instruction is less widely employed. It is extremely useful however when paired with a CTU, where up/down counting operations are required. Cars entering and leaving a parking lot, containers being filled and then emptied are just 2 examples of where paired CTU/CTD counters might be employed.
The elegance of the CTU/CTD pairing can extract a price however in terms of ease of use and program clarity. As the last exercise highlighted, one requires a very clear understanding of the operation of these instructions and the PLC's scan sequence, in order to employ them effectively.
This last exercise was definitely not the only way to setup an up/down counting sequence, but it does highlight the attention to detail that you will need to demonstrate when tackling the later sections of the next student exercise.
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PLC Exercise: Design a PLC ladder program for two floor elevator System. Make necessary assumptions as follows:
Assumptions:
• Lift door is manual sliding type. A door switch is provided to ensure the door is properly closed.
• In first Floor there is only Down Call Button
• Inside Lift, there are Both up and down button
• In Ground Floor there is only Up Call Button
Inputs:
Function Address
Up Call Button at Ground Floor I:1/0
Down Call Button at First Floor I:1/1
Up Button inside Elevator I:1/2
Down Button inside Elevator I:1/3
Door Switch (closed when door closed) I:1/4
Elevator up limit switch I:1/5
Elevator down limit switch I:1/6
Outputs:
Function Address
Lift Motor Upward Direction O:1/0
Lift Motor Downward Direction O:1/1
Ready to open door indicator Ground Floor O:1/2
Ready to open door indicator First Floor O:1/3
Ready to open door indicator inside Lift O:1/4
Solution: