Over Temperature Problem

chit gyi

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Oct 2007

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SINGAPORE

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• Mar 1, 2008

• #1

I have a problem encountering over temp alarm at my glue applying machine.The system is controlled by l5k using PID loop and SSR for on/off control of heaters.RTD is used for sensing tempperature.Over temp fault is frequently happen at the glue gun area.When this thing happen I disconnet the connector for awhile and restart the system.Connector is for heater and RTD wires.After a few week this thing happen again.My way is not correct to remove the error completely.Is there any way to find out the source of problem?Thank you all.

 

gmferg

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Modesto, CA

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• Mar 1, 2008

• #2

Is there only one output for SSR heaters, or multiple outputs to conrol multiple heaters (more outputs on = more heat)?

If there is only one output, PID is not a good fit. This should only require output to be switched on when a set low temp is reached and switched off when a set high temp is reached.

If there are multiple outputs, would need copy of code to see how outputs are staged on and off.

 

chit gyi

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• Mar 2, 2008

• #3

multiple out for multiple heaters.Input module is 1794-IR8/A and sensor is 100ohmPt385.Output module is 1794-OB16/A.

 

gmferg

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• Mar 2, 2008

• #4

probably just PID tuning required. Can you post your code?

 

chit gyi

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• Mar 2, 2008

• #5

I think PID tuning is OK.Now kp is 120,ki 1.3 and kd 710 for depandent gain.I suspect the vibration because the host is vibrating and connector is seated on the glue host.thank for reply.

 

godfrey

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Apr 2002

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Charlotte, NC

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• Mar 2, 2008

• #6

If the problem happens again a few weeks after clearing it, it is not programming or settings. Can you get the vibration sorted out?

 

chit gyi

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• Mar 3, 2008

• #7

When this thing happen again I will try to remove it from vibration.Now I can't do anything because main process is running continuously.It is a part of the process controlled by main process recipe data.Thanks

 

Lancie1

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Alabama

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• Mar 3, 2008

• #8

The cable connectors for heating equipment are likely to corrode after some time period. I have had trouble in the past with connecions near a heater element. Use connectors rated for high temperature. Copper or brass terminals do not last long. Silver, chrome, or platinum make for longer-lasting connectors.