Ladder question. one input, two outputs

[bugman746]

Bare with me, Im new at PLC programming. I am using a Micrologix 1100 with RSLogix micro. I have a small oven for powdercoating I want to start.. It has a fuel solenoid and a spark start system..

I want to be able to have one input that first open the fuel solenoid then approx 2 seconds later another output will fire the spark for 2 seconds then shut off spark.

So I toggle input, out put 1 comes on then 2 seconds later output 2 comes on for 2-3 seconds (lights burner) and goes off.

Im thinking this might be accomplished with TON timer?
any help greatly appreciated..

 

[jrwb4gbm]

This type of controller should be a fully approved UL device. Anything less could create a dangerous situation.
Having said that, yes, a TON timer can be used along with some Compare Greater Than instructions to accomplish this. I will not actually write or show you the necessary ladder code. The reason I will not do this is because of what I stated in the 1st sentence.


Edit:
+1 for what Bering C Sparky said in his post below.

 

[Bering C Sparky]

Hello,
You are on the right path with your thinking but there may be a few other things to consider. Answer these few questions first so we can better assist you.

1) Is this a school or practice project that will not really be operating an actual fuel fired oven or will this program be used to operate an actual fuel fired oven in real life?

2) Is your start switch going to be Maintained or Momentary?

3) Will there be some sort of thermostat that will control the temp of the oven and if so will this thermostat be turning the fuel valve output on and off?

4) What will your "Fuel" be? (Propane, NG, Diesel, Other)

The switch configuration is important to know in order to get your logic correct for latching/sealing outputs and timers.
If you are going to have a thermostat operation the valve for temp control then it will need to be added into the logic also.

If this is going to be a real fuel fired furnace you may want/need to have a sensor that will show if there is a flame present after the ignitor has turned off. (Actually a sensor that will show a lack of flame after the ignitor has turned off. (Flame Failure))
This will give you a way to shut off the fuel valve should there be a flame failure. If you do not have this then you run the chance of filling your oven with raw fuel. (Now you would have a bomb instead of an oven)
There are usually other safety devices to consider when building a fuel fired furnace such as Fuel Pressure Sensors and High/High Temp Safety Cut Outs, etc.

Lots to consider when playing with fire in order to keep things safe.

Give more information as to exactly what you have and what you are trying to do so we can better help/inform you.

Happy New Year
BCS

 

[bugman746]

This is an oven I run in my shop for powder coating metal. There is a type k thermocouple that runs a PID with a high limit that I will use to shut off propane solenoid if temp gets to high..

The input to start the ignition process can be maintained or momentary as I will make the contact in an HMI..


I have been working on an HMI using Visual Studio and Advance HMI..

It would be easy to make two buttons--one triggers propane solenoid the other trigger spark to ignight.. But I want to do the process with one button/contact..

 

[thaddiusjude]

This is just me.... but I would not run this straight out of a PLC. I would get a Honeywell Burner Controller or a FireEye and operate the burner controller with either discrete or modbus. Let the Burner controller protect you in the event of a lost flame or low gas situation. Do you have any pressure sensors on this system? Like a Dungs? Do you have a UV Detector to verify flame? All very important to keep you safe. These Honeywell controllers are not expensive.

Thaddius

 

[Steve Bailey]

This is not a place for a roll-your-own controller. Purchase an approved system.
If you should have a fire in your shop, your insurance company would deny your claim if you used a non-approved controller. Your local building inspector will most likely shut you down if he finds out about it.