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two Limit switches and one tz85 diagram


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miles&Jules
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Joined: 19 May 2010
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Location: ipswich QLD


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two Limit switches and one tz85 diagram

Is this possible to do?….we been using two relays attached to a botbitz esc and limit switches to control pickasso's winch pick…..it works but intermittently stops after a few hits…so thought we would try a tz85 but not sure how to make it work with two limit switches…can get it to stop with one limit switch …but how to connect two limit switches?…….any diagrams you guys can suggest? Crying or Very sad
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Post Mon May 11, 2015 5:01 pm 
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Nick
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How are you wiring up the limit switches and what sort of current capacity do they have? Many switches will be rated to carry a certain number of amps but do not like actually switching on or off with that level of current running thru them. The switches may have burnt-out contacts after a few cycles - can you test / open a used switch to check the contacts?
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Post Mon May 11, 2015 5:49 pm 
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James2



Joined: 07 May 2015
Posts: 115
Location: South Australia


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I can email a wiring diagram to you, that uses limit switches and then separate contacts to carry the current. (its for a roller door but its the same circuit) i'm adapting it to my bot.

I will have my modded one for my bot done by tomorrow and happy to send that with a parts list.

Post Mon May 11, 2015 7:11 pm 
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RogueTwoRobots



Joined: 12 Jan 2008
Posts: 135
Location: Irvine, Scotland


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I had this problem years ago when I had a crude electric axe powered by a windscreen wiper motor. Could get it to work with two limit switches when using the 'bang-bang' control approach but couldn't work out how to do it with a proportional ESC. Found this a few years later:

http://www.gimsonrobotics.co.uk/product_images/gla_limit-switch-circuit.jpg

Used it on my horizontal crusher (well, grabber Razz) to good effect, although because the actuator moved so fast, there was a split second delay between it hitting the switch and the switch breaking the circuit, so there is still a risk of slight damage (either to the weapon source or the switch if they're little/cheap ones) but better than having nothing.
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Post Mon May 11, 2015 8:12 pm 
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James2



Joined: 07 May 2015
Posts: 115
Location: South Australia


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wow, I have really over complicated mine (had a controller unit built in).

Post Mon May 11, 2015 9:02 pm 
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miles&Jules
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looks awesome guys….will grab some diodes at jaycar tomorrow. Very Happy
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www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Mon May 11, 2015 9:09 pm 
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miles&Jules
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Jaycar has 18v 1watt diods- how much wattage would it need? Should we try them and see what happens- we are running 4s 2000ah
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Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue May 12, 2015 12:11 pm 
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Nick
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The diodes could take quite high currents for a short period while the switch closes; it depends on you motor, gearing and how much weight is being lifted. I'd play it safe and go with 6A diodes. If you blow a diode, you can always run 2 or 3 in parallel to share the current.
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Post Tue May 12, 2015 12:17 pm 
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Knightrous
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Joined: 15 Jun 2004
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Location: NSW


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Alternatively, look at raiding some diodes from a car alternator, IIRC some of them extend into the 30-40A range depending on the model.
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Post Tue May 12, 2015 12:36 pm 
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miles&Jules
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Sounds like s good source aaron-we just tested it with a 775 motor and it works perfect Very Happy now to see what happens with the winch Shocked
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www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Tue May 12, 2015 12:50 pm 
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miles&Jules
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discovered these big boys on the bottom of some drills…they work fine. Very Happy
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www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Post Wed May 13, 2015 10:26 am 
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James2



Joined: 07 May 2015
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Location: South Australia


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this one is auto reversing.

here is one that uses 2 relays (one to take the current for one limit switch).
K1 is a DPDT (double pole double-throw)
S2 is the lower limit switch.
K2.1 is the upper limit.
can just add the speed controller to the start of the circuit. (can remove Rx1 &Rx2 with a ESC)

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Post Sat May 16, 2015 10:58 am 
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