Detecting solenoid ON and OFF state

[hevans1944]

Hard to say without being there to observe your problems. I realize utility power is sometimes unreliable in India, so perhaps using a large capacitor as a back-up power source makes more sense than trying to maintain the charge on a battery during long periods when everything is idle. You would have to use battery power management all the time, even with the looms not operating, to ensure battery power is always available when it is needed. Sounds like a real PITA. But, as you said, the capacitor charges quickly after power is restored, and if there is a subsequent power failure it will retain charge long enough for another orderly shutdown if, as you say, it only takes a few milliseconds to write data to the EEPROM prior to going into an orderly shutdown mode. I never try to second-guess a fellow who is actually on-site, elbows deep into the machinery. Sounds to me like you made a wise decision to use a large capacitor for backup power while you save the data to EEPROM. I can offer no better advice.

 

[Prakash123]

Yes, you are correct but in actual condition this is my real head ache problem that this will conclude my project. If this part successfully passed means I'm totally free to complete this project. So I've to tell to the customer to maintain the battery power as long as possible whenever the loom is in OFF condition. This may conclude my project but in customer side they don't know about real problem and they may think this may be a faulty product!!!

 

[hevans1944]

You don't need a backup battery for the loom. When the loom is turned off, the shutdown program sends data to the EEPROM which stores the information required to start up again. The EEPROM stores the data indefinitely, ready to be retrieved when the loom is turned on again... even if that is weeks, months, or even years later. You only need backup power for whatever time is required to execute the shutdown program when there is an unexpected power failure, whereupon you save data to the EEPROM for use when the loom is started again. Your large capacitor performs this function without any help from a battery.

 

[Prakash123]

Oh very very thank you. I'm just confused about this things. I was sad about capacitor charge holding time may decrease after a years. But your last post was clarified my all doubts. Once again very very thanks...