Burst Firing Module

LegacyUser

Can someone explain what this is exactly? I cant find a definition of what it is anywhere on the internet. My understanding of it is that its a power controller that operates in "bursts" whenever power is needed on the element it controls.

If the element devaiates away from the setpoint then the BFM will activate until the setpoint is reached again. am i right?? could someone give a more precise definition? thanks

DublinDilbert

Never heard of a burst firing module, and i've done quite a bit of work with power electronics and control systems...

What are you trying to control? some sort of heating element??
What sort of power source are you using?
What will measure the temperature?

Based on what you mentioned, i'd guess your looking for some sort of "on-off" controller ( the US guys like to call it bang bang control )...

LegacyUser

http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?D=Burst%20Firing%20Module&Nr=AND%28avl%3aie%2csearchDiscon_ie%3aN%29&Ntk=I18NAll&Nty=1&Ntt=Burst%20Firing%20Module&Dx=mode%20matchpartial&Ntx=mode%20matchpartial&N=0&name=SiteStandard&forwardingPage=line&R=2143890&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@0415936260.1193541567@@@@&BV_EngineID=cccgaddmghkmjmjcefeceeldgkidhgk.0&cacheID=ienetscape

theres an example of one. yeah im trying to control a heating element, so need something to control the amount of power that goes into it. im using standard mains power and using a platinum resistance thermometer to measure the temperature.

would you recommend another approach?? cheers for the reply!

DublinDilbert

Spogpean wrote: »

http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?D=Burst%20Firing%20Module&Nr=AND%28avl%3aie%2csearchDiscon_ie%3aN%29&Ntk=I18NAll&Nty=1&Ntt=Burst%20Firing%20Module&Dx=mode%20matchpartial&Ntx=mode%20matchpartial&N=0&name=SiteStandard&forwardingPage=line&R=2143890&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@0415936260.1193541567@@@@&BV_EngineID=cccgaddmghkmjmjcefeceeldgkidhgk.0&cacheID=ienetscape

theres an example of one. yeah im trying to control a heating element, so need something to control the amount of power that goes into it. im using standard mains power and using a platinum resistance thermometer to measure the temperature.

would you recommend another approach?? cheers for the reply!

Ahhh ok, its some sort of Triac ( a device used light dimmer switches... )

A solid state relay ( basically a TRIAC + drive in the one package ) is used alot in automation for turning on / off heating elements...

How accurate does you system have to be? can there be over / under shoots in temperature?

Are you trying to heat up some water and it can be plus / minus a few degrees? you can just use some sort of on/off controller... (RS Stock No. 339-0075 )

Are you trying to get a liquid to 45.755 degrees C exactly? If you can't have over shoots / under shoots ( some sort of chemical process ) you'll need PID or PI control to ensure the correct temperature... (RS Stock No. 250-0079 )

The above 2 RS numbers are just suggestions, they might not be perfect for your application... how much current does your element take? if its small you could pick a controller to control it directly, else if the current is too large you'll need a controller that can drive an external Solid state relay..

Also you'll find it difficult to get a controller to interface with a platinum resistance thermometer, most will use an NTC or thermocouple. Why are you using a platinum resistance thermometer?

LegacyUser

There's no particular reason for using a PRT, I thought that they would give the most accurate answer!!

well the project is a thesis, so im gonna have to experiment with proportional contro, then PI to show that the steady state error is being reduced. the end temperature has to be pretty similar to the setpoint. I was going to write a program in visual basic to control it with PI.

its a 2 kW heating element that im using, so ill need some sort of external controller, thats where the burst firing module or solid state relay comes in!

thanks for the replys btw much appreciated!!

DublinDilbert

Spogpean wrote: »

There's no particular reason for using a PRT, I thought that they would give the most accurate answer!!

well the project is a thesis, so im gonna have to experiment with proportional contro, then PI to show that the steady state error is being reduced. the end temperature has to be pretty similar to the setpoint. I was going to write a program in visual basic to control it with PI.

its a 2 kW heating element that im using, so ill need some sort of external controller, thats where the burst firing module or solid state relay comes in!

thanks for the replys btw much appreciated!!

Ahhh ok i see...

I would probably use a solid state relay to switch that sort of load ( 2KW = 9Amps, assuming 220V power supply )

with a solid state relay there's 2 ways you can switch it, you could turn it on for a % of the mains cycle ( this would require a zero cross detector ) or duty cycling it would involve turning the relay on for a number of seconds, then turning it off, the duty cycle is the ratio of the on to the off time... As the duty cycle increase so does the average power going to the heater.

Do you have some sort of output card set up on the PC your going to use for the control? There's some cheap NI USB daq devices which would probably do...