Triple-555 timer circuit not working in Proteus

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
I am new to 555 Timers and Proteus and I need help to fix a circuit I have built. The intended function of the circuit is as follows.

  • The logic is controlled by an external circuit but it is represented by switches within this circuit to purely test the 555 Timer functionality. The switches are user controlled in this circuit and they control which 555 timer must be turned on when logic 1 (ie. SW1/SW2/SW3 connected to VCC) is detected.
  • Only one 555 timer must function at any time as each 555 timer output has been configured with the use of resistors and capacitors to roughly drive the 24W 220V motor (depicted as a lamp) at respective speeds. The speeds configured by U1, U2 and U5 should roughly be 80V, 150V and 220V.
  • To illustrate an example, if U1 is switched on by logic 1 (ie. SW1 connected to VCC), the motor must be driven at 80V. U2 and U5 will be switched to logic 0 (ie. SW2 and SW3 connected to ground).

test4.jpg

I have used Proteus to simulate but I get the error below.

error3.PNG

I have reason to believe it arises due to incorrect isolation of the 555 timer outputs (logic gate that is combining the U1, U2 and U5 outputs) but I have been unable to find a solution. I have also considered connecting logic toggles at pin 4 instead of using VCC to switch the timers on. I am unsure if that is a better way to control which 555 Timer outputs a signal though.

It should also be noted that MCUs cannot be used. I would appreciation any suggestions to solve this.
 

dl324

Joined Mar 30, 2015
14,458
Welcome to AAC!

Why are you using switches to switch power to the timers? For astable operation, the first time period will be longer than what it will be after the device has gone through its first discharge cycle.

Have you verified that a single timer works?
 

MrChips

Joined Oct 2, 2009
26,077
Welcome to AAC!

Here is a suggestion.
Remove U4 and the rest of the AC circuitry.
Replace U4 with an LED. Monitor the voltage output at U6 pin-9.
 

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
Welcome to AAC!

Why are you using switches to switch power to the timers? For astable operation, the first time period will be longer than what it will be after the device has gone through its first discharge cycle.

Have you verified that a single timer works?
An external circuit will output either 100/010/001 on 3 connections to determine which timer must be turned on. I have used the switches to simulate this ie. connection to VCC represents 1 and connection to ground represents 0

I have verified that they work separately with a basic 555 Timer circuit but not in this circuit as it never simulates due to the error
 

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
Welcome to AAC!

Here is a suggestion.
Remove U4 and the rest of the AC circuitry.
Replace U4 with an LED. Monitor the voltage output at U6 pin-9.
Thank you for your suggestion. I have tried it but the error persists so I cannot monitor the voltage
 

dl324

Joined Mar 30, 2015
14,458
I have used the switches to simulate this ie. connection to VCC represents 1 and connection to ground represents 0
It would be better to use the reset input to enable/disable the timers, but you're still going to have that problem with the first on period being longer than the rest for your astable devices.
 

Alec_t

Joined Sep 17, 2013
12,803
I have never used Proteus, but don't you need to include a voltage source for Vcc, or at least define the Vcc value ?
What is the default operating voltage for the logic devices U6, U7 ?
Does the triac type need to be specified ?
 

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
It would be better to use the reset input to enable/disable the timers, but you're still going to have that problem with the first on period being longer than the rest for your astable devices.
Thank you for your suggestion. I did find that toggling on pin 4 worked better. I simulated a circuit using pin 4 to toggle and it produced good results up until the "mixing" of the 3 555 Timer outputs. I unfortunately lost and can't remember the circuit and when I tried to replicate it, the same error I posted occured
 

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
I have never used Proteus, but don't you need to include a voltage source for Vcc, or at least define the Vcc value ?
What is the default operating voltage for the logic devices U6, U7 ?
Does the triac type need to be specified ?
I am not confident in my knowledge of Proteus but I believe that the VCC I used is considered to be a power rail in simulation so a voltage source isn't really required. The voltage is also defined in a setting in Proteus.
I believe the operating voltage range of U6 is -0.5V - 7V. I'm not sure about U7 as I believe it is a generic part on Proteus
I have seen videos of people using the generic TRIAC so I don't think it needs to be specified. However, I am using a BTA06-600B TRIAC and when I replaced the generic TRIAC, the error still occurred.
 

Thread Starter

EdwardFran

Joined Apr 27, 2022
25
Try using the .ic command in the transient analysis to skip the initial operating point calculation.
Thank you for your suggestion. I am not confident in my implementation but from what I tried, I was unable to do this as the simulation fails immediately after debugging begins
 

eetech00

Joined Jun 8, 2013
3,147
I am new to 555 Timers and Proteus and I need help to fix a circuit I have built. The intended function of the circuit is as follows.

  • The logic is controlled by an external circuit but it is represented by switches within this circuit to purely test the 555 Timer functionality. The switches are user controlled in this circuit and they control which 555 timer must be turned on when logic 1 (ie. SW1/SW2/SW3 connected to VCC) is detected.
  • Only one 555 timer must function at any time as each 555 timer output has been configured with the use of resistors and capacitors to roughly drive the 24W 220V motor (depicted as a lamp) at respective speeds. The speeds configured by U1, U2 and U5 should roughly be 80V, 150V and 220V.
  • To illustrate an example, if U1 is switched on by logic 1 (ie. SW1 connected to VCC), the motor must be driven at 80V. U2 and U5 will be switched to logic 0 (ie. SW2 and SW3 connected to ground).

View attachment 265955

I have used Proteus to simulate but I get the error below.

View attachment 265957

I have reason to believe it arises due to incorrect isolation of the 555 timer outputs (logic gate that is combining the U1, U2 and U5 outputs) but I have been unable to find a solution. I have also considered connecting logic toggles at pin 4 instead of using VCC to switch the timers on. I am unsure if that is a better way to control which 555 Timer outputs a signal though.

It should also be noted that MCUs cannot be used. I would appreciation any suggestions to solve this.
The MOC3031 requires at least 15ma to trigger and is not the correct device for 220v. The MOC304x series should be used. The 4075 doesn't have enough output current to drive the opto LED, so you'll have to add a transistor driver. The TRIAC and snubber values and resistor/cap values may not be correct either but can't tell without a TRIAC part number.

BTW- you could design this using one timer....
 
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