8/14/2015 4:27 PM | |
Posts: 70 Rating:
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Hi, I saw your suggestions and now I know more or less the values to put. Now I'm trying to do the commissioning and I do the Pretuning and the Fine Tuning and although the program says that it's tuned it actually gives me an different temperature on the outlet comparing to the chosen setpoint. Why do you think this is happening? is it because the thermocouple acquirement period is higher than the cycle interrupt period? thanks for the help |
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8/14/2015 10:52 PM | |
Joined: 11/29/2011 Last visit: 8/19/2024 Posts: 1359 Rating:
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Hi, After you finished with SIMATIC S7 S7-1200 Programmable controller "9.2.7 Commissioning the PID controller", did you managed to switch the PID into Automatic mode? You can find info about this in "Table 9- 17 Data types for the parameters" where the State output detailed. Please upload a picture to visualize the problem. I hope I could help! |
- What you read here, please check with manuals and your requirements. |
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8/17/2015 12:42 PM | |
Posts: 70 Rating:
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Hi, Yes i switch it automatic mode and its still not working correctly. Even when it finished the tuning the output temperature was different from the chosen setpoint. And when I connected it to the HMI the difference was even higher. I have no clue about what is happening |
8/17/2015 10:11 PM | |
Joined: 11/29/2011 Last visit: 8/19/2024 Posts: 1359 Rating:
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Hi, From that distance hard to say, but... For me it looks like it is a "dead" time issue. Sometime Automatic tuning software does not deal with it very well. Maybe if you try to tune it manually you achieve a better performance. Anyways there is a mixer tap example including commissioning example here: 3-Point Stepper Control with SIMATIC S7-1200 (Set 2) I hope I could help! |
- What you read here, please check with manuals and your requirements. |
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8/18/2015 11:02 AM | |
Posts: 70 Rating:
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Hi, Sorry for que silly question but how can I fix a "dead" time issue? Is there any Siemens guide to help with the manual tuning? I have been using that example as guidance since the last week but unfortunately I had all this problems until now and I have no clue about what doing next because my knowledge in programming is very reduced Thanks for all your help |
8/18/2015 8:48 PM | |
Joined: 11/29/2011 Last visit: 8/19/2024 Posts: 1359 Rating:
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Hi, The application example should work just fine. The only comment I can make is try manual tuning based on this SIMATIC S7-1200, S7-1500 PID control manual under chapter:
I hope I could help! |
- What you read here, please check with manuals and your requirements. |
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8/24/2015 6:53 PM | |
Posts: 70 Rating:
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Hi, I had already done the pretuning and the fine tuning when all these problems appeared. I used the transition time shown in the characteristics of the valve, and later I measured and put the correct value. The temperature sensor is operational and very close to the valve (after of course). I tried to change to the PID_Compact and is functioning properly. How can this be possible? Thanks for all the help |
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