Outside heater source to Studio 5000

Leukic

Member
Join Date
Oct 2018
Location
Leesville
Posts
93
Hey everyone, it has been a little while i have had an issue.

I am having to add an outside heating source to cure paint on the slugs of brick. At the moment the heater is just manually cut on and off with the buttons on the heater. Now they are wanting the heater to run when the extruder clutch is engaged and cut off when it stops. When the extruder clutch is engaged slugs of brick are pushed out of the die onto a line headed to the setting table. When the brick line stops and if the heater continues to run it will dry the brick out way too much before it moves on down the line to be cut and stacked.
Here is a picture of the schematic of the heater. The on button is just a NO button and the off button(NC) acts as the seal in for the ON button once it is pushed in to start the heater.
vwwcar.jpg



Basically when the output for the extruder clutch to engage comes on I want the heater to start. And when the clutch disengages for it to cut off.
The issue I am having is the wiring/plc connection.
I am not sure if I will have to possibly add a relay and or rungs to the plc.
2ut3llh.png


I hope I made this somewhat understable.
 
You haven't said if you want to maintain the pushbutton functionality or not. That can make a difference in the complexity of what you are doing. I will assume to you want to keep the buttons and have them still function.

You will need to add two relays to the system; a start relay and a stop relay. You will need to add a few rungs to the plc program also. The first rung will use a normally open contact from the clutch output driving an on delay timer in parallel with an off delay timer. The timer timing bit (.TT) from the on delay timer timer will control an output that turns on the "start" relay. The timer timing bit from the off delay timer will control an output that turns on the "stop" relay. Set the presets for both timers to 1 second (1000).

Wire a normally open contact from the start relay in parallel with the start pushbutton. Wire a normally closed contact from the stop relay in series with the stop pushbutton. Voila, you're done.

There is an "easier" way to do it with one relay but that would make the buttons non-functional and the plc would have exclusive control of the heater.

Keith
 
You haven't said if you want to maintain the pushbutton functionality or not. That can make a difference in the complexity of what you are doing. I will assume to you want to keep the buttons and have them still function.

You will need to add two relays to the system; a start relay and a stop relay. You will need to add a few rungs to the plc program also. The first rung will use a normally open contact from the clutch output driving an on delay timer in parallel with an off delay timer. The timer timing bit (.TT) from the on delay timer timer will control an output that turns on the "start" relay. The timer timing bit from the off delay timer will control an output that turns on the "stop" relay. Set the presets for both timers to 1 second (1000).

Wire a normally open contact from the start relay in parallel with the start pushbutton. Wire a normally closed contact from the stop relay in series with the stop pushbutton. Voila, you're done.

There is an "easier" way to do it with one relay but that would make the buttons non-functional and the plc would have exclusive control of the heater.

Keith


While drawing some stuff out on my thinking board. I kinda figured I would need 2 relays. And just reading what you posted makes sense, I kinda have to keep use of the pushbuttons as per my site manager. Thanks Keith, Ill post more if i run into any issue
 
I'd probably also add a third relay that is closed by the heater when running. This would switch an input on/off for indication that the heater is running on an HMI, or if there is no HMI, to alert the PLC to take action based on the heater not functioning.
 
If it were me, I'd be looking at the possibility of adding a "local/remote" switch to the heater, such that when it is in "local" mode, the start/stop buttons operate as they do currently, and when it is in "remote" mode, the PLC has sole control via a single run/don't run relay contact. That would require changes to the heater circuitry, so if you don't want to do that for reasons of warranty, spare part consistency and whatnot, perhaps not the best option. But from a functional perspective, that would give you the best of both worlds, and also save you the inevitable headache when management goes "oh yes but on these bricks we don't actually want it to run like that, can you have the PLC ignore those bricks and let the operators use the buttons like they used to?"
 
Shawn that is a good idea. But in this setup the operator is basically infront of the heater alot! So he knows if it is running or not, It is pretty loud.

ASF another good idea. I am not really worried about warranty stuff with the heater but if something was to happen the operator can still push the stop push button and cut off the gas to the heater.
 
Shawn that is a good idea. But in this setup the operator is basically infront of the heater alot! So he knows if it is running or not, It is pretty loud.

Then you have better operators than I do. Once an action is automated where I work, all awareness, responsibility, and care for that particular action goes out the window. I kind of understand that attitude too, to a degree.

Good luck.
 
Shawn that is a good idea. But in this setup the operator is basically infront of the heater alot! So he knows if it is running or not, It is pretty loud.

For the sake of a $5 relay and $5 sounder, it removes another thing for an operator to think about, which is never bad.

If you control the heater via your PLC, anything that now goes wrong, will fall well and truly at your door.
 

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