2 pwm 555 driving 2 irf 4905 with on having adjustable duty cycle and fixed frequency and the adjustable frequency at fixed duty cycle all controlled by 1 dual 10k pot

• both are inductive loads
• need ability to adjust both sides independently for tuning purposes
• and once tuned control both with a single knob through a range

 

2 pwm 555 driving 2 irf 4905 with on having adjustable duty cycle and fixed frequency and the adjustable frequency at fixed duty cycle all controlled by 1 dual 10k pot

• both are inductive loads
• need ability to adjust both sides independently for tuning purposes
• and once tuned control both with a single knob through a range

Is this a statement that you have one or are you asking for somebody to design one? Next question is what frequency range and duty cycle do you require? Last question is are you sure this is the best way to accomplish this task?

 

this is to replace a burner control on a diesel cook top for a marine application the original control had 3 setting off low and high i want more adjustment and the replacement parts are no longer available so i hoped the hive mind might point me in a suitable direction. the pwm for the blower would be to vary the speed from 10 to 90% and the variable speed for the fuel pump would vary the pulse frequency to pump faster or slower

 

Do you know the the pump pulse frequency range you want to control with the dual pots for the 10% to 90% adjustment of the fan speed?

Also what's the pump pulse-width?

 

the pump will work with 25-75% as it is a pulse activated piston pump frequency from about 5 hz down to .5 hz

 

Is this a statement that you have one or are you asking for somebody to design one? Next question is what frequency range and duty cycle do you require? Last question is are you sure this is the best way to accomplish this task?

asking for help with the design

 

was considering an arduino or similar micro controller but the simple application of 555 or 556 is intriguing and much more cost effective
the original cooktop could be replaced but at a cost of $5500 i would prefer to replace the control circuit on the one i have
the rest of the system involves a few thermal relays to turn on the glowplug for startup and once hot turn it off and also for over heat shutdown

 

was considering an arduino or similar micro controller but the simple application of 555 or 556 is intriguing and much more cost effective
the original cooktop could be replaced but at a cost of $5500 i would prefer to replace the control circuit on the one i have
the rest of the system involves a few thermal relays to turn on the glowplug for startup and once hot turn it off and also for over heat shutdown

In order to design a 555 solution I still need to know the range of frequency and the dutycycle requirements. It also might be the case that the dual 10K pot might be unsuitable. More information about what the 555's will be controlling might be helpful, but I really need to know the frequency and duty cycle ranges.

Maybe it would be helpful to experiment and research this question with the Arduino before committing to a hardware design.

 

In order to design a 555 solution I still need to know the range of frequency and the dutycycle requirements. It also might be the case that the dual 10K pot might be unsuitable. More information about what the 555's will be controlling might be helpful, but I really need to know the frequency and duty cycle ranges.

Maybe it would be helpful to experiment and research this question with the Arduino before committing to a hardware design.

looks like arduino will be a good starting point then all i would need would be a couple of p-chan fet drivers hopefully with active complementary driving on both high and low states

 

Matching the PWM percentage for the Fuel, and for the Blower-Speed,
simultaneously from zero to 100%, with one Control-Knob,
might be quite tricky, not to mention, potentially dangerous.

Then there's the incorporation of the various Safety-Devices into the new Circuitry.

I wouldn't want to take the risk of designing Controls for this set-up unless I was doing it in person.

If You have to ask how to accomplish this project, you're probably not qualified to do it safely.

Do You have Fire-Insurance ?
.
.
.

 

Is there a problem with going to a dual pot resistance greater than 10kΩ?
It would help achieve the 10:1 range in pulse frequencies you want.

 

Matching the PWM percentage for the Fuel, and for the Blower-Speed,
simultaneously from zero to 100%, with one Control-Knob,
might be quite tricky, not to mention, potentially dangerous.

Then there's the incorporation of the various Safety-Devices into the new Circuitry.

I wouldn't want to take the risk of designing Controls for this set-up unless I was doing it in person.

If You have to ask how to accomplish this project, you're probably not qualified to do it safely.

Do You have Fire-Insurance ?
.
.
.

all the existing safety controls are in working order but i just need the timer portion to be able to adjust the fuel / air mix for fine tuning and maintaining as clean a burn as possible