Relay simulation in Multisim

Relay Simulation in Multisim

Relay: Relay is an electromechanical device that opens or closes a circuit in response to a current in another circuit. It is a current controlled switch. Relay circuitry can be configured to provide all logic functions such as AND, OR, NAND, NOR and any combination of these.

Terms:

Front contacts (Normally open N/O) are those contacts which are made when relay is energized (excitation voltage is applied to its coil).

Back contacts (Normally closed N/C) are those contacts which are made in absent of a proper excitation.

While choosing a relay consider following.

Pick up current.

Holding current.

Coil resistance.

Coil inductance.

Contact resistance.

In component data base relay can be found under

Place basic(symbol of resistor) --> basic virtual 

RELAY1A_VIRTUAL  is single pole normally open type.

RELAY1B_VIRTUAL  is single pole normally closed type.

RELAY1C_VIRTUAL  is single pole double throw type.

Coil resistance, inductance, on current and off current can be adjusted:

Double click on the relay and under value tab enter desired value. 

Make a simple circuit relay1 like this:

And click on simulation button. You may get an error message. Choose yes to allow convergence assistance to solve problem or on the ‘simulate’ menu select ‘Load simulation settings’ and load relay simulation.dat. select all and click ok.

Press space bar or click on the switch.

The two relays are equivalent to a single 1F/1B  (1 front 1 back relay).

 You can combine RELAY1A_VIRTUAL and RELAY1B_VIRTUAL to make relay with any number of poles.

4F/4B relay: Let us make a 4 front and 4 back contact relay by combining RELAY1A_VIRTUAL and RELAY1B_VIRTUAL. Wire the circuit as shown.

Virtual wiring: if you think the circuit is quite messy then use virtual wiring to make it look clean.

on work space right click and select properties (or press Ctrl+M).

on circuit tab, under ‘net name’ select ‘show all’

now make circuit virtual1 like this:

Rename net 3 to 2 and 4 to 0. this will virtually connect them. To do this, double click on the wire. In net name enter 2 and press ok. A warning message will pop up. Click ok on this.

Do same for net 4 and enter 0. in net name.

Now simulate the circuit.

Using virtual wiring, make 4f4b circuit it may look like: