Temperature variation +/- 5 degree centigrade.

Hello guys,
Induction oven heater inverter failed. we replaced it by vacon nxp 160kw type inverter.it is working fine but our problem is oven temperature is not maintained as per the set value.Oven temperature is variation +/- 5 degree centigrade.as a result wafer stick colour is showing little difference.
Please, could you help me, anybody, to fix the problem?
Kind regards.
Biti.

Please support me.
Thank you.

The part you listed is an AC inverter drive which is one component in your oven. The temperature variation could be caused by many different things and is not something that can be diagnosed by simply stating that the drive was replaced. You should be hiring someone who knows how to maintain and repair the oven as a whole unit to diagnose and repair it (like the manufacture).

since the inverter was replaced, have you done an auto tune with the temperature controller?
just a thought, since no one knows your system.
james

Thanks for support.
In the hmi there is no auto tuning option. Hmi only available set temperature, maximimum out put set, minimum out put set, over temperature shut down limit, and amplification.
Our set temperature set value 147,maximum out value 70%, minimum out put 45% and amplification set at 500 and over temperature shut down at 15.
Now temperature is going upside 152 and downside 144.between 144 to 152 maintain.
Temperature sensor signal going to plc and plc is giving 0 to 10v to the drive.
I am first time using the vacon drive so I have lot of confused about this drive. I want to know is it possible to set pid control. If possible how do I set. If you have any idea, how to set pid in inverter. Please help me to learn.
Kind regards.
Biti.

Biti > Induction oven heater inverter failed.

Biti > In the hmi there is no auto tuning option. Hmi only available set temperature,


I suspect you need to figure out how the original inverter controlled the temperature.
Usually inverters are controlling motors . . . and I assume this is a heater?

>>>
A proportional–integral–derivative controller (PID controller. or three-term controller) is a control loop feedback mechanism widely used in industrial control systems and a variety of other applications requiring continuously modulated control.
>>>

Was there a 'built in PID' in the original inverter? Or is there a separate PID
controlling the inverter and is the new inverter compatible with it? Or is
there a PLC reading the temperature and implementing the PID function in
its software?

I suspect you need to figure out how the system - as originally built - was
controlling the temperature and then replicate it . . . or add whatever is
necessary to control the temperature in a satisfactory manner.
Poet.

You have not given us much to work with. Firejo's suggestion is your best advice.

How closely were you able to regulate the temperature with the previous drive? Is the replacement drive the same model as the original? If not, I'm not surprised you don't get the same results. If the replacement is the same model, check to make sure all drive parameters in the new drive match those from the old drive.

Now remember I said earlier to follow Firejo's advice. If that's not possible here's my take on your situation from halfway around the world. My advice is free and worth as much as you paid for it.

From your description it sounds like the control loop is done in the PLC since the temperature feedback is wired to it and its output is the setpoint to the inverter. It also sounds like the control loop in the PLC may be proportional only and the HMI variable named "Amplification" is the proportional gain factor.
You could set up a means of graphically monitoring the temperature and the 0-10 volt signal to the drive. Once you have done that, try reducing the amplification and observe how the response changes and whether or not you can control the temperature within a narrower range.

Mad_Poet said:

Biti > Induction oven heater inverter failed.

Biti > In the hmi there is no auto tuning option. Hmi only available set temperature,


I suspect you need to figure out how the original inverter controlled the temperature.
Usually inverters are controlling motors . . . and I assume this is a heater?

>>>
A proportional–integral–derivative controller (PID controller. or three-term controller) is a control loop feedback mechanism widely used in industrial control systems and a variety of other applications requiring continuously modulated control.
>>>

Was there a 'built in PID' in the original inverter? Or is there a separate PID
controlling the inverter and is the new inverter compatible with it? Or is
there a PLC reading the temperature and implementing the PID function in
its software?

I suspect you need to figure out how the system - as originally built - was
controlling the temperature and then replicate it . . . or add whatever is
necessary to control the temperature in a satisfactory manner.
Poet.

Click to expand...

hello,
Original inverter and newly installed inverter is not same.Both are different manufacture.Original inverter parameter setup option was not available and all parameter adjustment was doing by software.
we dont have any previous parameter record with us and machine manufacture also dont mension the setup parameters in the circuit diagram.
Original inverter there was in built pid or not i am not sure but newly fix vacon pxn drive has pid control option.I will try and inform you.
Thank you for your suggestion.
Kind regards.
bITI.

Biti,


so if i have this correct, every thing was working fine with the old VSD and oven temperature was stable and controlling well. the VSD failed and was replaced with a Vacon unit.

since no parameters from the original VSD have been saved i would assume the Vacon VSD has normal setup parameters to match the motor its controlling.



Assuming its a re circulation fan or a combustion blower i think your issue is the drive setup.
i would suggest you look at this and match the VSD output for the process.

look at the following to match your process

0 - 10Vdc reference to drive and the output this applies to motor 0 - 100% (or whatever 0 - 50Hz, 0 - 2990 RPM etc)and set your output range to match process by parameters

acceleration and deceleration rates of VSD
the motor nameplate values, are they correct in the VSD ?


then analyze what is happening when you get a temperature change is the Motor rate speeding or slowing too quickly? if so fine tune until your back into control


take slow steps and very important change one setting at a time and check the effect if its better leave it if no return it to what it was.


Record all settings before you start to change anything.

Hello,
Good morning.
Kindly see the image. So that your doubts will be clear. It is not motor or combustion blower. It is working and production is going on but I am not satisfied.
OK, thanks for supporting me.
Regards.
Biti.

look in the PLC for a proportional and The K and ID parameters.