AcE_Krystal
Newbie level 1
Hi all, I'm new here but I thought I would give it a shot 
What I'm trying to do:
I'm trying to rebuild a arduino based Linear actuator controller for a 24Vdc 1,8A brush actuator.
- PWM controlled
- current draw feedback (for max.current protection)
I'm using examples of an open-source documentation that can be found here on page 9, but is really tiny tiny and not good to read.
Because of the bad quality I'm trying to make my own version of the schematics where I'm also looking for improvements here and there.
Questions:
I'm starting to get a hardware list already but there are a few points where I'm stuck or have questions:
Q1. It uses the LM358P, but I'm missing pin #4 and #8 (the V+ and V-). Are these pins not connected? Or is it common for schematics to not draw the V+ and V-?
Q2. R7 seems to be described as 4k7/10k. What does this value mean? 4K, 7K or 10K resistor is needed?
Q3. For the Flyback Diode D1 I'm planning to use the 4N5822 Schottky Diode, is this a proper diode for the job?
Q4. Can someone help me on how to calculate the needed Capacitor and Resistors for the current sensing circuit? I'm planning on changing some value's like other PWM frequentie but i have no idea how to re-calculate the needed values for the current sensing circuit.
Q5. I'm kinda confused with how to calculate the current sensing resistor.
I'm unsure because the formulla W=I*I*R gives me 0,71Watt what is way below 5W. Even having a buffer of 3x that value gives me only 3*0,71=2,14Watt.
Do I use the wrong formula for this?
Q6. Any other advice / improvements are welcome
I hope people can help me rebuilding/perfecting this part of the Schematic. I will edit the schematic with all the improvement/advice and upload the final version here, hopefully with a few formulas so people can recalculate it to there liking. =^.^=
What I'm trying to do:
I'm trying to rebuild a arduino based Linear actuator controller for a 24Vdc 1,8A brush actuator.
- PWM controlled
- current draw feedback (for max.current protection)
I'm using examples of an open-source documentation that can be found here on page 9, but is really tiny tiny and not good to read.
Because of the bad quality I'm trying to make my own version of the schematics where I'm also looking for improvements here and there.
Questions:
I'm starting to get a hardware list already but there are a few points where I'm stuck or have questions:
Q1. It uses the LM358P, but I'm missing pin #4 and #8 (the V+ and V-). Are these pins not connected? Or is it common for schematics to not draw the V+ and V-?
Q2. R7 seems to be described as 4k7/10k. What does this value mean? 4K, 7K or 10K resistor is needed?
Q3. For the Flyback Diode D1 I'm planning to use the 4N5822 Schottky Diode, is this a proper diode for the job?
Q4. Can someone help me on how to calculate the needed Capacitor and Resistors for the current sensing circuit? I'm planning on changing some value's like other PWM frequentie but i have no idea how to re-calculate the needed values for the current sensing circuit.
Q5. I'm kinda confused with how to calculate the current sensing resistor.
I'm unsure because the formulla W=I*I*R gives me 0,71Watt what is way below 5W. Even having a buffer of 3x that value gives me only 3*0,71=2,14Watt.
Do I use the wrong formula for this?
Q6. Any other advice / improvements are welcome
I hope people can help me rebuilding/perfecting this part of the Schematic. I will edit the schematic with all the improvement/advice and upload the final version here, hopefully with a few formulas so people can recalculate it to there liking. =^.^=
