DI forcing in Siemens PCS7
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In PCS7, in the FC ladder diagram, digital input values cannot be forced; when the variable table in the FC ladder diagram is modified to 1, it works for a while before being reset again. How to force DI? And how to reset it after forcing it? Please advise, experts
Create a test bypass, add an internal variable, and directly change the value of that internal variable.
This post was last edited by Accompanying you_RGiyw on 2020-7-25 09:22. It cannot be forced because of external input; is it reset within one scanning cycle? Is it written like in the image below, by directly setting M140.0? I’m a beginner; please advise me, experts
Writing it this way is fine; in fact, if you want it to be even more convenient, you can bring m140.0 to the interface – for example, create a test button and correspondingly generate an output signal, thus having a complete test interface. However, if this aspect is related to safety, as a precaution it’s still best to remove or disconnect the bypass when it is actually put into use.
In PCS7, all function blocks are CFCs; by utilizing these function blocks, it is possible to carry out simulation as well as implement mandatory functions