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I am trying to figure out how to control a dc motor with a momentary switch as a trigger and limit switches for stops. The trigger needs to be momentary because I need three of them in parallel at different locations, so that it will operate if any of them are pressed.

The simple sequence is as follows:

  • Press button
  • Motor runs forward until limit switch is pressed then hold
  • Press button
  • Motor runs reverse until limit switch is pressed then hold
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  • \$\begingroup\$ MCU controls motor with H-brigge type driver. Control buttons and limit switches connected to inputs. \$\endgroup\$ – user263983 Mar 16 at 1:07
  • \$\begingroup\$ Shared clocks for each switch, a debounce cap across each button to R to clock from all switches with a series R 100-220 ohms and /2 FF to an FET full bridge ESC. \$\endgroup\$ – Tony Stewart EE75 Mar 16 at 1:22
  • \$\begingroup\$ Hmm I'm having trouble finding the correct search term for toggle relays, but there's a chance you can use a break before make 2 pole pulse activated relay as it doesn't seem you're switching very often. Is the motor large enough that it must be contactor controlled, or can the limit switches be left in the power circuit? \$\endgroup\$ – K H Mar 16 at 2:57
  • \$\begingroup\$ Is the motor on the part that moves and pushes the limit switches? \$\endgroup\$ – Bruce Abbott Mar 16 at 3:52
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You can use a relay with two independent NO and NC switches, DPDT relay (last one on the right).

diagram of relay connections

Image source: Electronics Tutorials - Electrical Relay

This properly connected will inverse the polarity on the motor when the relay is activated.

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