4/1/2020 6:50 PM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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How big should the total value be? It ends at 32,767. The LOGO! can not more. |
4/1/2020 6:57 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
Well, I guess this will be sooner then end of the world :) But it will be enough for three year approximately. |
4/1/2020 7:24 PM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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Please explain more what you want to do. Maybe a solution can be found. |
4/1/2020 11:49 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
Well the number to be added each time would be much smaller, around 0.01 Can Logo deal with such small numbers? |
4/2/2020 2:29 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
ixo65, I didnt quite understand your weighting example. Here is what I am trying to do: I am calculating the heat energy from momental and average power. I have 2 sensors for temperature (Vorlauf, Rucklauf) and liquid (heating water) flow sensor. I have calculated momental power and then average it over some period (one hour for the test). The power results are in 5th row of LOGO display (first momental and then average power). Then I calculate the gained heat energy in that hour. That is displayed in the 6th row. I would need to store this value and then add it to new value which comes next hour. This is the part which I don`t know how to program. AttachmentTest program.zip (311 Downloads) |
4/2/2020 2:54 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
Because one hour is very long time for testing, I change a bit the program to be more "test friendly". The averaging time is one minute (you have to wait one minute to see the average value) and energy calculation can be done sooner with a press on C1 button, just to see it working. Some examples: Power 1000W (= 1kW) .... that means 1kWh energy in one hour. Power 1350W (= 1.35kW) ...... again 1kWh (because of rounding to lower number) Power 2730W (= 2.73kW) ....... gives a result 3kWh energy in one hour (because of rounding to higher number) If I want to calculate the energy in two hours, I need to store this value and add it to next one for the second hour. And so on... 32767 is big enough at this point. AttachmentTest program (shorter times).zip (323 Downloads) |
Last edited by: Frayer at: 04/02/2020 14:56:10 |
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4/2/2020 3:43 PM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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Hello Frayer, take a look at attachment. It's a possible solution. This solution counted your kW/h up to 999.999 kWh. With a litte trick and two counters more you can count up to 999.999.999.999. AttachmentTest program (shorter times)_V2.zip (344 Downloads) |
4/2/2020 9:36 PM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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Attached is a proposal on how you can save and add up the exact energy value in W/h every hour. If you inserted in your program then must you the follows: You have to reference your calculated energy value per hour to B011 (parameter V1). The value of 32,767 is also only for the simulation. In your program must you set to 0. AttachmentCounter.zip (321 Downloads) |
4/3/2020 1:26 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
Hi, I put it together and now testing it. So, if I want to avoid rounding error, I have to calculate in Wh not kWh. That means the result will be in bigger numbers. This is a little bit unclear, because we are used to kWh. Maybe I will rather stick to your first solution with kWh and daily reading, I haven`t decided yet. I will test both versions and then decide. Can you tell me what is the purpose of "Protection active" setting of some bloc (I mean in general)? P.S.: Don`t be mad at me, I have to correct you since I am an electrician: the correct unit for energy is Wh (or kWh, MWh, Ws....) not W/h This is because you calculate the energy from power with equation " Energy (Wh) = Power (W) x time (h) " See "Misuse of watts per hour" in Wikipedia:https://en.wikipedia.org/wiki/Kilowatt-hour |
4/3/2020 3:09 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
Maybe you understood me, but I didn`t you. I didn`t know what you meant with 32767 limit, now you explained that you mean a V1 value of B003 (I thought you mean max. energy sum). This is what I am talking about the problems with communication over net with few sentences - one person always thinks the other knows what he means, but it is not always like that. OK, I don`t expect this V1 value (average Power) be ever high as that. Listed max. power of the machine is around 9000W. Please, check out this program, is it correct joined now? I noticed one small problem: timer B010 was quicker then averaging time - when B010 gives a "hour pulse" the average hour value was not ready yet (I tested on LOGO in real time). So the first hour was no energy added. Next hour was OK since the last result of averaging stays. AttachmentCombined test program.zip (316 Downloads) |
Last edited by: Frayer at: 04/03/2020 15:11:02 |
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4/3/2020 5:23 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
ixo65 you helped me a lot and I am thankful for that. |
4/4/2020 8:11 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
I have looked for a better solution, but i don't use an additional counter for the sensor. It may be also good with your principle with some little changes. I also have added counters, but check this for a fault, i am not perfect. The power is added in an arithmetic instruction every second. If the sum exceeds 3599 (3600), you have 3600 Ws = 1 Wh and the Wh counter will be increased. After 1000 Wh the kWh counter will be increased and the Wh counter will be resetted. Try out the program in attachment, maybe this help you. Regards, Scorp AttachmentTest2.zip (285 Downloads) |
Last edited by: Scorp at: 04/04/2020 20:12:17Last edited by: Scorp at: 04/04/2020 21:59:28 |
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4/5/2020 3:42 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
Maybe the problem now is solved with minimum of changes, but you have to check this for all conditions. 1. The adding time is reduced to 0.2s, therefore we need a value of 3600*5=18,000 to increase the Wh counter. This value is high enough to add 10,000 W in any way, you never exceed the maximum of 32,767 of the arithmetic. If you have 17,999, you can add 32,767-17,999=14,768 W maximum. 2. The threshold trigger now has a time 06:98s, the low flow warning has a time of 06:00s. If it is possible, then increase the time to 7s or 8s. If this time is too large, then divide the gate time by 2 and double the constant V3 or halve the constant V4 of B004. You also can use any other gate time, but be careful for bad rounding in B004, otherwise you will lost accuracy. Good luck with testing, Scorp AttachmentTest3.zip (276 Downloads) |
4/5/2020 6:28 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
Sorry for Siemens, but i have tried a simulation for an Eaton Easy E4 in ST (structured text). Just need a little time and get a solution with high accuracy. For me the program is better readable and also is very short. The advantage over the Logo is the 32 bit calculation without the internal rounding and more flexibility in structured text, if you use the right sequences. If the next Logo version in autumn don't have a much better firmware and software, then i know, what i will do in the future. Up to now i have only tested a few applications with the Easy E4 and i see more potential, 12 bit resolution for analog inputs, much more inputs and outputs possible, indexed addressing possible, structured text available and so on. If you are interested, see attachment. Regards, Scorp AttachmentEasy E4.zip (300 Downloads) |
4/5/2020 11:05 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
If it is the impulse generator 0.2s, then we have a problem also with other times. But you can test the next version with time 1.0s and same trigger 18,000. Then you have n*5Wh in the first counter, that doesn't matter. Count up to 200 for 1kWh and multiply Wh with 5 for the display. The accuracy is not lost, only the last digit is rounded to 0 or 5. The problem also may be missing subtractions, overflows in the arithmetic or counter pulses are lost, but i see no problem in the moment. If the power display is okay, then there should be no decreasing of accuracy. How do you manipulate the program to get ~10,000 W without the sensor ? Regards, Scorp AttachmentTest4.zip (282 Downloads) |
Last edited by: Scorp at: 04/05/2020 23:08:11 |
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4/6/2020 8:24 AM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
And the test program with fixed 10kW for check out:
AttachmentTest4 (10kW fixed).zip (395 Downloads) |
4/6/2020 1:15 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
There was a timing problem, when adding higher power values, then the counter gets no clock signal sometimes, too often. The problem is solved, but you have to clean up the diagram. Now there is an asynchronous adding and subtracting inserted. The cycle timer is 1s again, 0.99s on and 0.01s off. The positive edge is used for adding. With the cycle timer an additional timer is started, creating 4 impulses after 0.1s, 0.3s, 0.5s and 0.7s. These impulses are to subtract the values >3600, this is 14400 W maximum. If this is not enough, then you can reduce TH and TL to 0.05s to increase the amount up to 8. The complete time must be within the high signal of the cycle timer. I have tested it in a real Logo, exactly 10000 kWh after an hour. After testing you must rebuild the old connections for the right calculation, deleting the stopp watch and creating your desired display. Good luck, Scorp AttachmentTest5.zip (338 Downloads) |
4/6/2020 8:00 PM | |
Joined: 2/22/2008 Last visit: 8/6/2024 Posts: 2698 Rating: (207) |
In attachment the final program for you, i hope. The threshold trigger for the sensor is also good with a gate time of 1s, but directly connected to the power calculation block. The new timers are placed in upper position to see the connections directly. Regards, Scorp AttachmentTest6.zip (348 Downloads) |
4/7/2020 8:49 PM | |
Joined: 12/3/2018 Last visit: 1/22/2024 Posts: 76 Rating: (0) |
After a day of testing I think that`s it. Scorp, ixo65 and the others, thank you very much. |
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