DELTA and SIMATIC S7-300 PLC programming skill Test 1
What is the purpose of this project?
In this project, I wish to write a PLC control program to control the 16-Floor Simulator system using a DELTA PLC and a VEIVIEW HMI device that is already designed a while ago. To know more about the 16-Floor Simulator system, click HERE.
To view the performance of the 16-Floor Simulator system in action, click HERE.
To control the 16-Floor Simulator System, I will need a second PLC to execute the “Ladder Logic control” program which will be specially generated for this project. In this case, I will be using a Siemens S7-300 PLC to control the DELTA PLC through the execution of the control program.
From Figure 1, notice that the DELTA PLC has 3 inputs to control the direction of the analog hand indicator and 2 output signals to indicate the status of the “indicator”. Obviously, these inputs/outputs should be hardwired to the output /input ports of the second PLC which in our case is an S7-300 PLC as illustrated in Figure 2.
Figure 1: Shows the schematic of the 16-Floor Simulator System using a DELTA PLC.
Figure 2: illustrates the hardwired connection of both I/O terminals of the two PLCs
What is the purpose of generating a second control program in this project?
Developing a control program such as this can be specially used to find out how much “time” it can take for a novice PLC programmer to develop a control program similar to the one presented here. Of course the less time it takes for one to develop a similar code, the better. If one can develop such a control program for a PLC in about an hour or less, that is good. It means such a person, has the ability, knowledge, and talent to become a good PLC programmer in the future. I usually use these types of small practical test programs when I tend to test the programming skills of applicants when they apply for a PLC programming job opening.
A little information about the DELTA PLC input/output terminals
As depicted in Figure 1, I/O terminals of the DELTA PLC control the whole Simulator. The system PLC is programmed such that when X0.2 = X0.4 = 1 (switched on with 24 V DC), the indicator revolves CW (clockwise) which simulates the Cabin traveling upward. When X0.3 = X0.4 = 1, the indicator revolves CCW (counterclockwise) which simulates the Cabin traveling downward. Anytime the indicator is pointing at floor # “1”, Y0.1 = 1 and stays “ 1” as long as the indicator does not change its position. Anytime the indicator travels from any floor # to the next or to a previous one, Y0.0 is going to shift from 0 to 1 and back to 0 in 0.5 seconds. Anytime the X0.7 = 1, the small Lamp image on the HMI device turns on. The Lamp image turns off when X0.7= 0.
How the Control program should work?
You are given the hardware as depicted in Figure 2 in which the second PLC is hardwired to the Simulator as shown. You are asked to develop a code for the second PLC (SIMATIC S7-300) to control the 1st PLC as following:
STEP 1: When PB1 = 1 (I0.2) depressed momentarily (depressed and release for 1 second manually), the indicator to revolve (from any current floor number it is indicating) in CCW direction to point to the 1st floor. While the indicator is pointing at Floor # 1, Q0.7 turns “on and off” for 2 seconds (with a period of 1 second). At the end of the flashing time, Q0.7 is turned off and control of the main program starts execution of STEP 2.
STEP 2: The indicator starts rotating in CW direction to pass floor number “2” and right at the time it gets to indicate the 3rd-floor #, it again stops and starts flashing Q0.7 as mentioned earlier). At the end of the flashing time, Q0.7 is turned off and the control of the main program continues from the execution of STEP 3.
STEP 3: The indicator starts rotating in CW direction to pass floor number “4” and right at the time it gets to indicate the 5th-floor #, it again stops and Q0.7 starts flashing it was mentioned earlier. At the end of the flashing time, Q0.7 turns off, and the execution of STEP 4 starts.
STEP 4: The indicator starts rotating CW to pass floor number “6” and right at the time it gets to indicate the 7th-floor #, it again stops and starts flashing Q0.7 as mentioned earlier. At the end of the flashing time, Q0.7 turns off, and the execution of STEP 5 starts.
STEP 5: The indicator starts rotating in CCW direction and repeats steps 2, at floor # 6, step 3 at floor # 4, and finally step 4 on floor # 2. At the end of step # 7, the system is placed in “stand by” status and re-executes all the mentioned steps when PB1 (I0.2) is re-depressed.
Please also be informed to use SIMATIC S7-300 PLC which is used in this project, you need to configure the PLC hardware before to start developing the control software. The hardware configuration shown in Figure 3 is the one I had when I was developing the code.
The name of the folder holding the solution program for this project is 16Floor Sim_Test 1 and the control program named as “16_floor.s7p”. To download the folder, please Click HERE