Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

OB100 programming

Created by: autlago at: 3/19/2014 2:20 PM (16 Replies)

Rating (4)

Thanks 9

Result pages:: |; 1 | 2; |

17 Entries

Entries per page: 10 | all

3/19/2014 2:20 PM	Rate (0)
autlago Posts: 7 Rating: (0)	hi, I'm new, and i want to know how to program OB100 please. thanks.
autlago Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

3/19/2014 2:39 PM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 12/13/2024 Posts: 5697 Rating: (715)	Hello, Depends on what you would like to do at PLC startup. So please some more information. regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
Suggestion To thank Quote Answer

3/19/2014 3:33 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 12/23/2024 Posts: 15531 Rating: (2461)	autlago hi, I'm new, and i want to know how to program OB100 please. thanks. Prior poster is correct. If this is your first plc project using your first plc system (meaning, you have not used any plc before using the Siemens portal software), then might I suggest try designing your system such that it not need anything in the first scan OB. If you are more experienced, you already know it is not always possible, and for the few instances where you need to restore to a known proper system state, putting logic in the first scan OB is often the most straightforward approach. For example, your first scan logic may need to determine whether it was a power outage or a simple plc stop/start (like after a non-trivial plc download), then set startup state for your various processes to handle each situation properly. Sometimes we might establish some system state that latches on and the only time it is ever turned off is during the first-scan logic, meaning, once it is setup, it does not require being setup again until you lose power or restart the system. The less you need to put into the startup OB, the more likely it is you understand the problem and solve properly. Other system designers may have better and [probably] very different ideas and suggestions.
	science guy
Suggestion To thank Quote Answer

3/20/2014 1:45 AM	Rate (0)
autlago Posts: 7 Rating: (0)	hi, I've alredy done some programs, but I use just the block OB1. here is how i see the issue : as you know for every system that we want to automate, we shoud define the "initial state". the system should be at this state at the startup to excute the program correctly ( example : for an automated system for marking boxes, at the startup the piston rod must be at the entry position !) , so my quetion is how can i " make " may PLC to make sure that my system is at the correct inital state, then it can work properly. thanks.
autlago Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

3/20/2014 2:33 AM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 12/23/2024 Posts: 15531 Rating: (2461)	autlago hi, I've alredy done some programs, but I use just the block OB1. here is how i see the issue : as you know for every system that we want to automate, we shoud define the "initial state". the system should be at this state at the startup to excute the program correctly ( example : for an automated system for marking boxes, at the startup the piston rod must be at the entry position !) , so my quetion is how can i " make " may PLC to make sure that my system is at the correct inital state, then it can work properly. thanks. The first scan logic can help you with telling your program logic the current state is unknown. Then you can setup your logic to slowly and safely allow the user / operator to reset the system either manually or automatically depending on the mechanics and system sensors and device feedback. Nothing in the first scan can cause outputs to the real world to activate but it can put the system into a known state even if that is the unknown state. If your piston rods have position sensors you can use those to reset startup state for those devices that you know 100% where they are.
	science guy
Suggestion To thank Quote Answer

3/20/2014 3:07 PM	Rate (0)
autlago Posts: 7 Rating: (0)	so i can program that without using OB100, as i understand your remarks ?
autlago Posts: 7 Rating: (0)	Last edited by: autlago at: 3/20/2014 3:11 PM
Suggestion To thank Quote Answer

3/20/2014 4:07 PM	Rate (0)
Marciano Bronze Member Joined: 4/30/2007 Last visit: 3/9/2023 Posts: 231 Rating: (23)	Hello autlago, you could use the 'OB1_SCAN_1' byte from OB1 TEMP interface to know if is a CPU restart. But like huggy_d1mentioned , you need use sensors to know your machine position. That's normally call as 'basic position' or 'home position'.

Suggestion To thank Quote Answer

3/20/2014 6:59 PM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 12/13/2024 Posts: 5697 Rating: (715)	Hello, You can useOB 100 to set a Bit. Then you know in your cyclic program that your machine is in a unknown state. Then you can ié do a homing process. After completion of that process you reset the Bit. Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
Suggestion To thank Quote Answer

3/20/2014 10:34 PM	Rate (0)
autlago Posts: 7 Rating: (0)	Hi, Could you please show me how to do that in step 7 ? thank you for your help :)
autlago Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

3/20/2014 10:43 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 12/23/2024 Posts: 15531 Rating: (2461)	autlago Hi, Could you please show me how to do that in step 7 ? thank you for your help :) With cylinder position switches (or what I call cylinder prox's), you can detect the current position of the equipment and upon system startup set the current state. The problem still remains even with those switches, you may be 99% of full stroke forward or backward in the piston, and for proper operation you need 100%. What I do is train operators how to restart the equipment. If the customer or your supervisor requires automated restart (after operator presses a restart button), you can detect the current position, turn on appropriate device output to ensure piston is 100% full stroke, then do whatever your process requires. If you are asking us how to write your program, you have come to the wrong place. If you have a specific question about how to program a specific task, you may get 10 very different answers. Most likely you will get similar answers to my own that say, what have you written already and what works and what does not work. I personally use a lot of sequencers to set up and proceed through various machine states. I haverestart sequencers. Setup sequencers. Run sequencers. Fault handling sequencers. Each takes the tasks and executes as required for the process and does them in the proper steps as if done using manual control, but much more efficiently because we can operate more than one device at a time in automatic mode and in manual, that is often tricky to do - especially with Siemens HMIs. Is there a multi-touch HMI?
	science guy
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on