DSP Sine wave inverter error messsage : "No feedback loop "

[thannara123]

I have the above board ,it is available on our local market ,In which Dspic30F2010 is used .It has two mode inverter and UPS mode .
I have made a lot of inverter with this board .
But now i am experiencing with an error message on lcd "No feed back loop "
I know these problem arise from transformer transformer sensing section . [because if didnt connect the transformer primary to the working board will show these message ]
But here my transformer is working well .

is there anybody use this type of invreter ? , is there any help .

Thanks .

 

[nikhilmahasvar]

Have you connected the transformer drain ? If not it may sense as no feedback. If yes check the feedback section in the LM324.

 

[thannara123]

Have you connected the transformer drain ? If not it may sense as no feedback. If yes check the feedback section in the LM324.

transformer drain means connected to the transformer , Yes connected ,And works for one or more second and goes the error "No feedback " then the output will turnoff.
I checked LM324 section is the section from current transformer ?
I changed LM324 also ?
Is there any way the to get the schematic ?

thanks

 

[nikhilmahasvar]

There will be some high value resistors coming from AC output and it will be going to the LM324 I/P pins the output of LM324 will be 2.5V level shifted SW wave. Plz check.

 

[thannara123]

There will be some high value resistors coming from AC output and it will be going to the LM324 I/P pins the output of LM324 will be 2.5V level shifted SW wave. Plz check.

yes there 680k
but the resistor in my board its wrongly 68K
thanks i will change and tell the result

thanks

 

[thannara123]

Nothing happens. In which pin of dspic30f2010 sense for the " No feedback " error message

 

[nikhilmahasvar]

LM324 is used as diff. amp just trace the O/P is going to which pin. I you check in dc in meter mode you will get only 2.5V which is the avg. value. If you have a DSO you can get the sw signal at the fb pin. else you may have to chk in AC mode and you will get few milli volts as signal

 

[thannara123]

may i check the all(4 o/p) output pin of the LM324 ?

 

[nikhilmahasvar]

Plz chk the datasheet of LM324 check only the O/P of the section in which the FB signal is coming from INV O/P through high value resistors.

 

[thannara123]

Two Ac signal coming via high value resistor to the LM324 .These two output of the lm324 is going to the pin second and third pin of the DSPIC30f201
I tried out too much which one i cannot recognize which one is ?

 

[nikhilmahasvar]

From O/p Phase and neutral there will be resistors going to one opamp's inv & non inv pins. Pls chk the output of that.

 

[thannara123]

Re: DSP Sine wave inverter error messsage : "No feedback loop "

That pin is 14 th pin of LM324. At the output pin am getting 4.62 volt dc.with respect to ground
Volt mesured by multimeter

- - - Updated - - -

is there any way to find the schematic ?

 

[nikhilmahasvar]

Re: DSP Sine wave inverter error messsage : "No feedback loop "

you should get 2.5V in all O/P pins. In one Opamp of the LM324 there will be a voltage divider which will make 2.5V from 5V I/P plz check that divider your issue will be solved.

 

[thannara123]

Yes that was the problem

Thanks ..

 

[nikhilmahasvar]

Good.You are always welcome.