Timeline for Controlling Solenoid Valves with ULN2003A, Inrush Current, Arduino
Current License: CC BY-SA 4.0
6 events
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| Oct 14, 2018 at 10:52 | comment | added | matt__chv |
@Whit3rd The hold phase starts when the plunger stalls. The boost (which is just another word for stronger: sometime just full supply voltage, sometimes even boosted voltage -hence the name) is when the stronger voltage -hence current, hence force- is applied to allow movement. Once actuation is over, PWM is a very common choice to reduce dissipation. Mentioning PWM was needed -in my opinion- to explain how the current in hold phase is specified with a lower value than needed in activation - boost- phase (as otherwise stall current would be higher, since there is no back-EMF).
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| Oct 14, 2018 at 7:54 | comment | added | Whit3rd | The 'boost' phase starts with the plunger stalled, i.e. no significant back-EMF. That is identical to 'hold' current, is it not? PWM is not necessary nor indicated here. | |
| Oct 13, 2018 at 20:10 | comment | added | matt__chv | many question in a comment :) high-level your approach is correct, my main point was to share some background as to why it was likely the peak current is likely higher than the figure you had in your question. The final decision depends on how your circuit is built and the valve you end up choosing. | |
| Oct 13, 2018 at 11:33 | comment | added | Chris1309 | Are you referring to a voltage booster? My plan was to use one 12v power supply for the solenoid valves and to use a buck converter to get 5v from the 12v supply to power the Arduino and control of the ULN2003. I would then hook up GND of the valves to the ULN2003 (plus 12v VCC to 9) and VCC of the valves with the 12v supply. If I understand you correctly, your point wouldn't be an issue if the power supply can supply enough current (800 mA per switching valve). The transistor doesn't have to support 800 mA because back EMF will make sure the current that flows through it doesn't increase? | |
| Oct 13, 2018 at 6:27 | history | edited | matt__chv | CC BY-SA 4.0 |
added 105 characters in body
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| Oct 13, 2018 at 5:42 | history | answered | matt__chv | CC BY-SA 4.0 |