I looking for a component or a circuit that able to do loop like explain below - Page 1
Forum section: electronics / beginners

author: athtrya
author_rank: Newbie
timestamp: June 20, 2019, 09:31:55 am
content: The problem, I have system with 8 input and only 1 output, so I need to do a scan on all the pin and if 1 input pin is on this should stop the scan and active the output, when the input go off the scan restart.I know it's possible to do it with a microcontroller but I think more reliable in the long time by using a dedicated component it's also help for the long time reparability. (And also I'm not capable to do the code for the microcontroller anyway)The diagram if this can Helphttps://docs.google.com/drawings/d/1hHYEHJ7nMK8Jk5SwAXiAzeT2Aa1DrbVbUVVygmKjdf4/edit?usp=sharing

author: Brumby
author_rank: Unknown
timestamp: June 20, 2019, 09:43:39 am
content: Your requirements are very poorly specified - so while the following suggestion would appear to provide you with what you want, please forgive me if this suggestion isn't suitable....A 4078B logic chip. It's an 8 input OR/NOR gate.

author: athtrya
author_rank: Newbie
timestamp: June 20, 2019, 11:38:53 am
content: I have add the diagram hope this can help

author: LateLesley
author_rank: Frequent Contributor
timestamp: June 20, 2019, 12:36:08 pm
content: You're probably looking for something like a multiplexer chip. In the old 74 series, it would be something like the 74151.https://www.esi.uclm.es/www/isanchez/apuntes/ci/74151.pdfYou would need other components with it, a 3 bit counter to cycle through the inputs, and a clock to cycle the counter, but with an enable pin which stopped the clock when the output was high.

author: Brumby
author_rank: Unknown
timestamp: June 20, 2019, 02:44:47 pm
content: I can't see any reason to have a scanning process. The 8 input logic gate would seem to do what you want - unless there's some requirement which you haven't detailed.The scanning idea seems to be making a simple task rather complicated.

author: athtrya
author_rank: Newbie
timestamp: June 20, 2019, 04:10:52 pm
content: I think I want to be to generic in my explanation, so I will do my best to explain what is the problem, basically I have 4 independent thermostat with 2 output (1 for the heat mode and one for the cold mode) because the system can work for only one room at a time, I need to consider one thermostat at a time and ignore all the other, on the first thermostat in the list stop the system should go to the next thermostat. I hope this is more comprehensible.The electric diagram :https://docs.google.com/drawings/d/13cVFqC3f59bVOeFhP9_CU9sYCNWWfTaEBA5-BGjkcWk/edit?usp=sharing

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 20, 2019, 05:41:21 pm
content: Quote from: athtrya on June 20, 2019, 09:31:55 am8 diodes and 1 or 2 resistors will be a good OR switch ymmv.

author: Benta
author_rank: Super Contributor
timestamp: June 20, 2019, 06:54:25 pm
content: A priority encoder might be easier than scanning. Check MC14532 from ON Semi.

author: athtrya
author_rank: Newbie
timestamp: June 20, 2019, 07:50:15 pm
content: Quote from: Benta on June 20, 2019, 06:54:25 pmDo it's the correct wiring :https://docs.google.com/drawings/d/1iNkgy5VQibc2iy2YiCYSBtnrbGuP8LWhJaEtB2nn6M8/edit?usp=sharingThis seems logic to me but in the simplified diagram I take off all the PIN that aren't strictly use in the principle I have also ignore different voltage (but I know that I need the VDD and the VSS and I have to convert the voltage because all the contactor coil are in 220v)

author: athtrya
author_rank: Newbie
timestamp: June 21, 2019, 08:54:12 pm
content: I have add some new information in my previous post