×

Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Rotary Switches - Shorting Vs Non-Shorting

Webinar Questions

Forum Posts

Courses

Blog

Tech Articles

Ask questions about webinar lessons here. To see the Previous Webinars for a complete list of archives tuning webinars. 

= Resolved threads

Author
4371 Views

Hi Guys

Hope you are all wellI'm looking at buying a couple of rotary switches for the project of fitting a PDU to a Porsche 928. Which application would the benefits of either Shorting or Non-Shorting Rotary Switches. the two I'm looking at are from Farnell and switches are below.Non-Shorting - 56SD30-01-1-AJN - Rotary Switch, 12 Position, 1 Pole, 30 °, 200 mA, 115 V, 56 SeriesShorting - 56SD30-01-1-AJS - Rotary Switch, 12 Position, 1 Pole, 30 °, 200 mA, 115 V, 56 Series

Could I have some guidance in to what switch to choose and some understanding of Non-Shorting Vs Shorting Please.

Regards Liam

Shorting = the two adjacent pins are temporarily shorted (connected) before the first is released (disconnected) --- "make before break" (also noted as MBB)

Non-Shorting = the first pin is entirely disconnected before the second pin is engaged --- "break before make" (also noted as BBM)

A shorting switch ensures that there is *always* a signal to the receiving brain box. During the short, the current will pass through the smaller of the two dividers (least resistance). If a non-shorting switch is used there is a "dead-zone" where no signal makes it to the brain. Non-shorting can cause issues if whatever you're adjusting is quite sensitive in its signal refresh rate. A good debounce code in the brain can take care of that (if you have access to such code/parameters) - but if there isn't any debounce in the signal you run the probability of signal instability (and momentary system chaos). That instability may not be a big deal in your system - it may be huge - especially if you're on the opposite end of your spectrum (say going from position 10 to 9 and 10 is max voltage vs not connected being zero volts to the brain).

If your application is strictly to support on/off connections (e.g. daytime running lamps + fog lamps + rally lamps) then it's likely irrelevant which you choose.

Hi Kenny

Thank you for your reply, I thought that was the case. I was just looking for reassurance. made the use a lot clearer thanks again.

One of the switches is for the exact reason of controlling the lights.

Much appreciated

Regards Liam

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?