DC latching solenoid

[Miguel_V]

Your question is blank.

Regards,

[mem]

I don't know what the original poster intended to ask, but I have noticed that the DC latching solenoids in the Electro_Mechanical group (for example, the CONTROL_2C) don't seem to work.  At least not for me.  Clarification on using these parts would be greatly appreciated.

I'm using Multisim Power Pro Edition 12.0.0 (12.0.653), Database version 12.0.a.

Thanks.

[Tayyab_R]

Hi,

Here is a very simple example of how to use the control coils in Multisim. If you double-click on the component, you can specify the on/off currents and resistance/inductance.

Hope this helps.

[mem]

Would you please look closely at the circuit you provided and then explain to me how you think it works?

Thank you.

[mem]

....more importanly, please explain why it works.

Thanks again.

[Tayyab_R]

Hi mem,

What I am doing in the example is just connecting all the inputs for the relays to a 12V supply and output to ground. These can be connected to anything really. The main connection is the connection to the control coil. If you double-click on the part, it will bring you to the value tab where you can configure the on/off current etc for the coil. You need to have a resistance between the coil and the power supply to ensure that the required current is being supplied. The switch is just to turn the coil on and off and see the required behavior of the circuit.

Hope this helps.

[mem]

Thanks for your reply.

Perhaps I'm making incorrect assumptions regarding the CONTROL_2C component. 

I am assuming that it models a DC coil that controls the states of two normally open (NO) sets of contacts, and two normally closed (NC) sets of contacts.  The schematic symbol used for this component would suggest this model.

In the "normal" state, with no voltage applied to the coil, the terminals of the NO contacts remain disconnected ("open"), with very high resistance existing between the contact terminals, and the terminals of the NC contacts remain connected ("closed"), with very low resistance existing between the contact terminals.

In the "energized" state, with the appropriate voltage applied to the coil, the states of the contact terminals are reversed; the terminals of the NO contacts are now connected (or "closed"), with very low resistance existing between the contact terminals, and the NC contacts are now disconnected (or "opened"), with very high resistance existing between the contact terminals.

Given the assumptions above, the way you've constructed your circuit, the 12 VDC power supply is shorted directly to ground through the two NC contacts.  It can't possibly work.

But yet, it does! 

So my question is, if the CONTROL_2C component does not model a coil with two NC contacts and two NO contacts as described above, what does it model?  How does the model behave? 

More to the point, why does the model behave as if there is high resistance between the contacts, even when they are closed?

I'm clearly missing something here.

Thanks for your attention to this.

[mem]

I think I understand what I was missing.....

The 12 VDC power supply is essentially modeled as an ideal voltage source.  It will provide whatever current required to maintain ~12VDC, even across a shorted set of contact terminals.  There were no power-rated components included in the circuit that would indicate such non-physical conditions.

So, a few questions for NI:

Is there better component choice to use to model a real voltage source?

Can the DC power source be configured in a manner to limit the output power?

Can the DC power source be configured to indicate faults (e.g. when working into a short)?

Is there a power-rated version of the DC voltage source?

Also, with regard to the CONTROL_2C component.  I've attached two identical circuits; one using the CONTROL_2C component from the component database included with my version of Multisim, and one using the CONTROL_2C component that Tayyab included in his/her post above.  In my installation of Multism, one circuit works (_NI_K1), and the other doesn't (_K1).  I'm not sure why.

Any insight regarding these issues will be greatly appreciated

Thanks.

[Tayyab_R]

Hi,

To answer a few of your questions, the reason one circuit is simulating while the other isn't is because the model for the component has changed in version 12.0.1. The model parameters a very high resistance which caused simulation errors. As a workaround, you can copy the component from my file and use it when necessary.

There is a NON_IDEAL_BATTERY component in the Power_Sources group. You can model some internal resistance in this component.

You can not limit the output power from a DC/AC Source in Multisim. You can try to look into some of the controlled voltage sources like the ABM_VOLTAGE source which allows you to use a mathematical expression to define the voltage.

Hope this helps.