Questions about one module of the central control DCS ECS700
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The image shows the operation module DIO-21V of the cut-off valve. When the valve is operated manually to be opened, as shown in DO, it will display ON and turn green. However, if the EMOPN (interlocked opening) signal is ON, DO will neither turn ON nor change to green, yet the valve physically moves. What is the principle behind this? Or have I missed something, perhaps there is an oversight? Please advise
1. As for the interlock action causing the DO to remain OFF, that’s because the interlock is directly connected to this DO point; the program sets this DO to either 1 or 0, so the line corresponding to this DO point is neither ON nor green. 2. The DO for manual operation of this valve turns ON because you use a function block to set this DO to 1; thus, once that line turns green, the DO point also turns green. 3. This is just my personal opinion; you can take it as a reference.
There’s an issue with the program’s code; perhaps the definitions of internal and global variables are incorrect
Based on what you said, I’ll try to understand it better
This does not involve global variables and local variables
What kind of valve is this? What is its state when there is no power supply? Does the ‘on’ setting mean it should be turned off or on? The answer should be here
It’s just a cut-off ball valve; ON means open
When 700 is online, the output acts first, and then the module operates; it’s not the case that the output from the module triggers the action of the terminal.