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???
09/20/10 08:02
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 		 #178593 - No there is no hysteresis.
Responding to: ???'s previous message
1. The Error (Set Value - Present Value) decides the amount of Power that goes to the heater. This is executed every second.

2. In every half cycle; the TRIAC is fired (4 pulses), so that it gives the proper voltage to the heater, as decided in Step 1.

As simple as that.

There is just one restriction: After power ON, if the temperature is below 100 Deg.C, then we can give Maximum 30% Power to the heater. else we can give the power as decided by the control logic.


List of 41 messages in thread
TopicAuthorDate
What is the reason for Heater blowing.            01/01/70 00:00      
   Hof often/how we?            01/01/70 00:00      
      Some more information...            01/01/70 00:00      
   continuous rating            01/01/70 00:00      
      This could be the reason...            01/01/70 00:00      
   Way too much current...            01/01/70 00:00      
      Some more information required...            01/01/70 00:00      
   do you have hysteresis in your control?            01/01/70 00:00      
      No there is no hysteresis.            01/01/70 00:00      
         Four pulses?            01/01/70 00:00      
            The Heaters are failing, electronics is OK.            01/01/70 00:00      
               Why Pulses?            01/01/70 00:00      
                  I will do just that...            01/01/70 00:00      
                     Processor must know about zero-crossings            01/01/70 00:00      
               ??            01/01/70 00:00      
                  soft start            01/01/70 00:00      
                     Soft Start            01/01/70 00:00      
                        an easy and interesting check            01/01/70 00:00      
                           Soft start, again...            01/01/70 00:00      
                  Yes these heaters need Soft start            01/01/70 00:00      
                     Again: Power? Voltage? Current?            01/01/70 00:00      
                        Avoid driving gate all the way to next zero crossing            01/01/70 00:00      
                           Crest factor/power factor correction            01/01/70 00:00      
                     Phase angle control...            01/01/70 00:00      
                        I agree with you.            01/01/70 00:00      
                           Good luck!            01/01/70 00:00      
                           are all heating coils the same ?            01/01/70 00:00      
                           There You Go            01/01/70 00:00      
         re the possible need for hysteresis            01/01/70 00:00      
         Power? Voltage? Current?            01/01/70 00:00      
   Alternate Heating Control Algorithm            01/01/70 00:00      
      Some more clarification...            01/01/70 00:00      
         Voltage - or power? [ed]            01/01/70 00:00      
   The other controllers            01/01/70 00:00      
   Thanks All members.            01/01/70 00:00      
   just suggest..            01/01/70 00:00      
      Reply to JecksonS Ben            01/01/70 00:00      
         Good point!            01/01/70 00:00      
            supposed to            01/01/70 00:00      
         opto isolated triac            01/01/70 00:00      
   My solution            01/01/70 00:00      

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