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Help with S7 1200

Created by: palavras at: 3/27/2013 10:24 PM (4 Replies)

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3/27/2013 10:24 PM	Rate (0)
palavras Posts: 5 Rating: (0)	Hi to all, I am newbie in PLC’s and I have a project to do: One input activate a counter (down) which is counting 10 steps, from 10 to 0(zero) and the actual step number must display in HMI. Each step last 1min and enable 4 outputs. please Help!!
palavras Posts: 5 Rating: (0)
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3/27/2013 10:41 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 1/17/2025 Posts: 15541 Rating: (2465)	palavras Hi to all, I am newbie in PLC’s and I have a project to do: One input activate a counter (down) which is counting 10 steps, from 10 to 0(zero) and the actual step number must display in HMI. Each step last 1min and enable 4 outputs. please Help!! If you understand a state machine, you have many ways to create the state machine that represents what you are looking to do. If you do not have a starter kit or at least the HMI, PLC, and input simulator at your desk to learn, it may be difficult to become proficient with the S7-1200 PLC programming. What have you tried so far?
	science guy
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3/27/2013 11:05 PM	Rate (0)
palavras Posts: 5 Rating: (0)	Thanks for your fast replying. I have in a desk the plc s7 1200 and hmi. That I have tried is to made a simple level control via two level switch. But that I want now to do is more complicated. Do you have any suggestion to make my state machine and display it on HMI. Thank you in advance.
palavras Posts: 5 Rating: (0)	Last edited by: palavras at: 3/27/2013 11:12 PM
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3/28/2013 1:43 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 1/17/2025 Posts: 15541 Rating: (2465)	palavras Thanks for your fast replying. I have in a desk the plc s7 1200 and hmi. That I have tried is to made a simple level control via two level switch. But that I want now to do is more complicated. Do you have any suggestion to make my state machine and display it on HMI. Thank you in advance. There are several ways to make a state machine in your PLC programming. I tend to go with simple to build and troubleshoot using something like this: -\| first scan \|---[setup state machine]-- -\| system interruption \|---[adjust state machine as required]-- { like E-Stop or system stop } -[SeqStep=?10]---\|do step 10 logic\|--[set NextStep = 20]- -[SeqStep=?20]---\|do step 20 logic\|--[set NextStep = 30]- ... this is last step in this phase of state machine -[SeqStep=?999]---\|do step 999 logic\|--[set NextStep = 0]- -\|move NextStep -> SeqStep]- if you need more than one distinct set of states, like "INITIALIZE SEQUENCE", "SETUP SEQUENCE", "MANUAL SEQUENCE", "AUTOMATIC SEQUENCE", you can designate ranges of the states, like 10-99 for INIT 100-999 for SETUP 1000-1999 for MANUAL 2000-2999 for AUTOMATIC Then to know what sequencer selection, you can monitor your SeqStep tag to be within your defined ranges to set the sequencer mode, and can quickly create mode change states in the 20000-29999 range, like changing from auto->manual and manual->auto. There may be specific physical things to change in order to initiate auto mode with perhaps some time delays for systems to pressurize, stabilize, and so on. Step 7 provides state machine instructions, but it is more difficult to show people how they work, and the logic on works in step 7. The above logic is relatively universal among most plc ladder logic choices and is very easy to visually troubleshoot for most technicians. Rarely do engineers need to get involved to diagnose system problems when these types of state machines are used, or at least that has been my experience. You can write logic only you can troubleshoot, or you can write it so almost anyone can pick it up in 5 minutes almost on their own. I choose simple over elegant and efficient where possible. Perhaps this is helpful. As for displaying the system state on the hmi, you can set text lists based on the state machine states, display the text from the text list in a text box, and the state is now available on the hmi.
	science guy
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3/7/2016 10:37 AM	Rate (0)
Min_Moderator Platinum Member Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4766 Rating: (122)	New question published by AutoGen_578643 is split to a separate thread with the subject Save project in MMC and send it to technical people for insert it in PLC?. Best regards Min_Moderator

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