I have a system where there are 8 inlet pressure measurements from 8 different channels. In my system, I am trying to maintain the pressure in a range using hysteresis.
Here, I want the compressor to switch on even if one of 8 pressure measurement drop below a certain value (say 0.2 bar). But, I tried to connect the one output to the compressor from each input. Then realized that multiple inputs from my 8 channels are to be in a OR function to run the compressor even if one of the pressure channels are below pressure.
How can I separate the hysteresis output from each of the 8 channels to get an output turn on even if one of the pressure falls below?
I tried using msg.topic but I am making some mistake as I couldn't compare the topics.
8 channels read pressure - 8 hysteresis loops for each channel - write the output (switch on) the compressor even when one value is below set point.
If you already have the 8 channels and 8 hysteresis nodes set to provide a 1 if they need to be switched on then you don't need anything fancy, as any node outputting a 1 should be aa signal to act - not matter where it comes from... so just wire all of them into a node that just looks for a 1... or am I missing something ?
Ithank you very much for the replies. Though I found a method, I happen to have better understand on how to improve it.
I thought having multiple inputs to one node to switch on the compressor might have contradicting signal. When I instead of having one particular output node, had 8 separate nodes that pointed to my compressor, it got on for one second or so and switched off later.
This is something that can be avoided if I have one compressor node and 8 inputs going to it (instead of 8 comp, and 8 nodes)?
I don't understand what you mean. Can you post the flow for what you have so far please so that I can better understand? So from the pressure inputs through to the compressor output. See this post for how to post your flow - How to share code or flow json
I could not reply to you as I had met with an accident and was not able to work!
Thank you for answering anyways and I found that my flow had an issue may be due to the node red version of it (v0.17.5).
Multiple inputs with opposite values for eg: 0 and 1 are the inputs to the particular node with operates the blower in my system. But, when varying inputs are given, the blower shuts off after starting for a second or so. So, I used a function with OR statement to give me an output of either 0 or 1.