Why are you putting a "diode" at the HLK-5V? Maybe to prevent CN2 from forcing voltage into HLK5? That's OK, then
Also, why do the wires reverse direction, that's ridiculous...get organized & draw from left to right. Your power supply section is nicely drawn (other than Vcc & 3V3 improperly drawn as a 4-way dot).
470 ohms? for r1????...way too much
Q2 & Q3 are WRONG...redo them the emitters must go to gnd R 3/4 should be maybe 500 to 5k ohms, not 10 ohms!
get a badge that says Practice makes perfect. it's worth the time to make it right.
You need a fuse at CN1...no AC line powered item should overlook that. May be include a MOV (varistor) as well
When in the dark remember-the future looks brighter than ever. I look forward to being able to predict the future!
Hi Kartman and avrcandies , thanks.
that Schematics is Wrong,
updated Schematics is Attached,Expecting yours suggestions on that.
Can you measure the leakage current between the 0V of the HLK-05m05 and mains earth using the AC current range of ,say 200mA using your multimeter? I'd be expecting 100 or so uA of leakage.
Tell us more about the inputs - there's a magnetic loop detector input which you say is relay contacts and is connected by 60m?? of cable. What relay is used here? The reason I ask is there is usually a minimum current required for switch/relay contacts in order for them to work properly. Once we know what relay, then we will have a minumum current required. This will guide further design decisions.
AD5 should have an RC filter right at the adc pin...you don't want to pick up a bunch of noise? That also prevents (greatly reduces the chance of) aliasing. Also, the resistor gives some protection--say you accidentally apply 12v to the connector--POW!!
Maybe add 200ohms series to the pwm line...it's not full-blown protection, but helps guard against "oops"...otherwise tapping a high voltage (like 12V) to the connector pin is an instant & total AVR destruction.
thanks avrcandies ,
modifications Attached, please suggest.
Why 10us for the time constant for the analog input? What signal are you expecting? 10us might be a transient. As well, your code must filter any incoming signal.
Are you going to measure the power supply leakage? It might be enlightning to you.
Expecting Loop detector output signal as 0(low) and 1(high) , digital signal.
i will measure and Update
So what is a ‘digital signal’? It doesn’t describe the voltage or current involved. In the real world digital signals are analog values with noise and other nasties.
Is the processor a plug in module (what your drawing shows) or is the processor soldered to your board?
Why use a module that offers essentially nothing?
plug in Module, not soldered, it is essential.
Module? is this what you call an 'ic socket'? You still haven't responded to my questions yet. Remember, these are for your benefit, not mine.
here is the details,
1.CN3 and CN5 connectors soldered,on that , Serial to Ethernet Module Inserted. I am sending the data from PC via Rx and TX(UART)
2. For Atmega328P Controller, IC socket soldered.so that we can insert Atmega328P IC and remove.
3.Insted of ADC5, I am Using PB0(PIn no:14).
OP doesnt reply to the most of the questions....
I dont understand of the point of insterting and removing. the IC here plays a major rule in the application as I understood, so having it soldered directly to the board is the normal! you are just adding more cost to the board...
thanks Moe123 ,
I will Solder directly to the Board as your suggestion,.
That tells me very little. Re-read my questions.
It is not unreasonable to use an ic socket ('module'!!) - makes it easy to change the AVR. If you were putting the circuit board in a vehicle or something that vibrates, then using a socket might not be a good idea.
I will follow your suggestion,
PB1 is getting Low(0V) and High(5V) from IR sensor.
PB0 is getting Low(0V) from Induction Loop detector(60cm long from IO pin (PB0 ) to Loop detector). Internal pull up activate.
Both IO pins ESD protected .
Any protection Please suggest.
Just because you put an ESD diode on the input doesn’t mean you’re protected from ESD. It is only one step. Your pcb layout will affect how well this device performs.
You might want to use a lower value pullup resistor to get a little more immunity from noise. Have you taken into account any potential leakage from the ESD diode?
You still haven't responded with the power supply leakage measurement. The results might surprise you.
thanks Kartman ,
You still haven't responded with the power supply leakage measurement
Existing PCB not Available, tomorrow i will get and measure.
Have you taken into account any potential leakage from the ESD diode?
No, need Help on this.
ESD with pull up, Attached Image
Diode leakage - page 2 of the semtech datasheet. Reverse leakage current 5uA max @ 25C. Can only assume it gets much worse with temperature, but they don’t tell us. Also note the junction capacitance and clamp voltage specs.
How did you determine the pullup value of 1k5?
How did you determine the pullup value of 1k5?
I need help on this( I am just select lower value resistor), Please help .
You need help to calculate the current leakage and you need help to calculate the needed pull-up resistors ? and you are doing AC supplied applications + automotive ? I dont want to be mean....but dont you feel guilty that some peoples lives will be put into danger ?
you need help to calculate the needed pull-up resistors ?
I need to help on this,
I think you are ignoring the main question. You are doing application in India to Automotive customers, yet you lack the basic fundementals to make sure that these applications are safe to use. Dont you think that you should slow down a bit and give this work to another expert in your company ? or are you the only "expert" there ?
thanks a lot Moe123 ,
I know about Pull up Resistors,
what I am asking, With TVS diode, what might be the Pull up resistor (as per the kartman),
With TVS diode, what might be the Pull up resistor (as per the kartman)
I think its better to make it more clear: If your product reached one customer, and this customer faced a danger or something....then its all your problem and you might go to prison and your company would face a big penalty! So at the moment I think you might want to pass this work to someone else in your team who has more experience.
I wonder which automotive company might outsourced these products to these people!!!!
I’ve asked before - what is the specification of the device driving this input? We know it some kind of magnetic loop detector. We need to know the type of output - is it dry relay contacts, opto transistor, open collector transistor etc. for example i was using a device earlier this week - its datasheet told me the output was 3V at 20mA. This is the type of information you need to work from, otherwise it’s a guess.
1. PB0 Pin connected to Induction Loop detector, which is giving Low out , PB0 Internal pull up activated, so that PB0 as Input not floated. I can Read Low(0V) .
2. PB1 pin connected to IR sensor, which gives Low output(0V) and High Output(5V). I can read 0V and 5V.
for Both we don't know current .
We need to know the type of output - is it dry relay contacts, opto transistor, open collector transistor etc.
IR sensor, which gives Low output(0V) and High Output(5V). I can read 0V and 5V.
so you mean a DIGITAL IR sensor ? you mean a voltage output...something like proximity sensor from Avago APDS-9120 or perhaps something THT mounted via a cable like the old TSL261RSM:
for Both we don't know current.
you dont know how to measure current ? but earlier you told me that you have electronics and hardware design background....you heard about Ohm's Law ?
1. PB0 Pin connected to Induction Loop detector,
Can you provide more info on this detector circuit, maker, part number, or link to datasheet please.
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