"Latching" relay in control circuit

[soulcramp]

I am designing a control circuit for a device at work. I am operating five 12VDC motors that are controlled by their respective momentary pushbuttons running through a series of relays. I have a main relay that distributes 120VAC for the coils of my relays as well as the 12VDC for the motors. I need to create a type of loopback in this circuit in order to latch the main relay until a limit switch is tripped causing the common leg of my 120VAC to open, and releasing the coil on my main relay.
I used to do this kind of control circuit quite a bit years ago but have gotten extremely rusty and keep second guessing myself. I have a copy of Multisim but each time I try and run the simulation, it fails.
Any ideas on a simple self-latching relay design that might work for my application? I can send a copy of my schematic if it will help.

Thanks guys!
Justin

 

[MikeMl]

Remember how to draw "ladder logic"?

 

[soulcramp]

Yes and no. I used to write ladder logic as it applies to PLCs, mainly Allen Bradly and similar equipment. This circuit shouldn't be giving me this much of a headache!

 

[MRCecil]

The limit switch (nc contacts) should be in series with your holding contacts on the control (120V control contactor/relay). When the limit sw. opens, the control drops out. If holding contacts haven't been configured into the design, then I would recommend that is done.

 

[Reloadron]

You want to modify something like the attached relay latching circuit.

Ron

<EDIT> I shoul;d point out that in the circuit shown there are other contacts that would supply the load. The circuit only shows a single set. The pin numbers were based on a relay I use frequently. </EDIT>

 

[MrAl]

Hi,


Just to add to the information already presented a bit, they do make latching relays that are made to latch one way or the other and then back the other way on command. They are fairly easy to use too. Check out the web for such devices if interested.

 

[soulcramp]

Thanks all,
Looks like I had it right to begin with. The problem I am having must be with my Multisim software.