Discussion and advice on logical interlocking diagrams
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There are two questions about logical interlocking. I hope experts can give some advice! logical description: There is an interlocking between a shut-off valve EV101 and a fan C101, which requires: 1: If shut-off valve EV101 is closed, fan C101 is also closed. Likewise if the fan C101 is closed, the shut-off valve EV101 is also closed. 2: If the shut-off valve EV101 is opened, the fan C101 is also opened. Likewise if the fan C101 is opened, the shut-off valve EV101 is also opened. How to draw this logical interlocking diagram? There are two pumps P101A and P101B that transport media in the same pipeline. The pumps do not have on-site operation support and have a remote control cabinet. Require: 1: Both pumps A/B can be started at the same time. 2: One of the two pumps must be running at all times, e.g.: Pump B stops, then pump A must run and cannot be stopped. Otherwise, pump A stops and pump B must run. Logic diagram.JPG (576.05 KB) 2009-3-2 13:11 Is this logic diagram correct, and what is the logic of the red line? Maybe I shouldn’t post it in this forum (it has been posted in several forums: lol), but I will post it for everyone to take a look and see if there are any experts who can give me some advice.
first question: The shut-off valve and the fan are controlled by the same signal source, that is, one signal is output to two devices at the same time. Same on and off. Just think of these two as one device. second question: Logically, there should be no problem. There are two conditions for starting the A pump. If one of them is met, it can be started.: 1.A When the pump is running automatically, pump B stops. 2. Click the start button of pump A. The start button is the normally open point, and the stop button is the normally closed point. (Not marked in the figure) Both operations send out pulse signals. (Not marked in the picture) Then there is the problem of the red line. Haha, the function of the red line is to maintain it. After the starting pulse is reset, the run command is maintained. If P101A is on, it will run, if it is off, it will stop.
What you said above is quite reasonable and the thinking is so flexible. I will also learn from it.* Got it! But why can’t I give you a score? Also, in the second picture, should a NOT gate be added to the P0101A remote stop to be correct? This post was last edited by Feng Qingqing on 2009-3-3 10:41 ]
Thank you, I burst into tears, finally someone recognized it, haha. The P101A remote stop wiring in the second picture should be the normally closed point, no need to add NOT ； If NOT is added, the wiring must be connected to the normally open point. :lol
You are in third grade and can only give 2 points. I cannot give you more points.
So that’s it, I threw 10 minutes and 20 minutes, no wonder I couldn’t throw it out.
You should be economical, you can throw away at most 20 cents a day, don't spend money like water.
The two signals or gates of the fan on and the cut-off valve open form one signal, and the two signals or gates of the fan off and the cut-off valve close form one signal. These two signals pass through two RS triggers respectively and trigger each other to control the opening and closing of the fan and shut-off valve. It's a bit difficult to describe, and the graphics are more intuitive, but I won't upload the graphics, so I apologize.
Why are start and stop connected with AND in the second picture?
I feel that in the second one, a NOT gate should be added for remote stop. For example, if the stop signal is 1, the output after adding the NOT gate is 0, and after ANDing, the output is 0, and the pump stops. I don't know if it's right, I hope you can give me some advice.