Induction brass annealer redux

[GrocMax]

I'm new to this forum and I'm just getting started into reading this thread so i might have missed an early discussion about the power supply ON/OFF input. Any reason why the remote ON/OFF function on the power supply was not used (pins 13 & 14) versus using a heavy duty relay/contactor to switch on and off the 48VDC? This is an optical isolated input that controls the PWM of the power supply. Does it take to long to power up under an immediate load?

If you are referring to the RSP-750-48 PS, no, the remote switching feature doesn't have a fast enough rise time to fire off the tank circuit in the induction board, its more of a controlled 'soft' start. A key to getting the boards to work correctly (and not blow up mosfets) is you MUST hit it with a fast rise time (like a spark ignition coil), so the PS output(s) needs to be ON and near peak voltage. I suppose it would be entirely possible to get it to work if there was some form of precharge circuit, but a relay is 5 bucks and simple and lasts.

There are other features of the newer fancier switching PS that appeal to idiots like me who don't want to 'release the schmoo' in their electronics, that make up for that one flaw.

 

[ottsm]

If you are referring to the RSP-750-48 PS, no, the remote switching feature doesn't have a fast enough rise time to fire off the tank circuit in the induction board, its more of a controlled 'soft' start. A key to getting the boards to work correctly (and not blow up mosfets) is you MUST hit it with a fast rise time (like a spark ignition coil), so the PS output(s) needs to be ON and near peak voltage. I suppose it would be entirely possible to get it to work if there was some form of precharge circuit, but a relay is 5 bucks and simple and lasts.

There are other features of the newer fancier switching PS that appeal to idiots like me who don't want to 'release the schmoo' in their electronics, that make up for that one flaw.

Figured something was an issue or someone would have tried it. I have a lot of Arduino stuff lying around and if I take on this project (still thinking about it) I'll probably just do all the timing and control with the Arduino and an I2C LCD display I have.

 

[GrocMax]

I did try it. Almost released the schmoo, but the auto low voltage shutdown of the PS saved it.

 

[Jose_Luis_G]

I'm new to this forum and I'm just getting started into reading this thread so i might have missed an early discussion about the power supply ON/OFF input. Any reason why the remote ON/OFF function on the power supply was not used (pins 13 & 14) versus using a heavy duty relay/contactor to switch on and off the 48VDC? This is an optical isolated input that controls the PWM of the power supply. Does it take to long to power up under an immediate load?

Easy answer to that.
It happens that the inductor needs instant power, not a slow growing voltage and amperage as happens when you switch on the power unit with the inductor already connected.

 

[ottsm]

International rectifier makes a half bridge driver chip IR2153 (or newer equivalent chips) that has the ability to shutdown the gate driver outputs with low voltage, this could eliminate the relay. Anyone find a commercial induction unit that still cost effective but uses the IR2153 versus the self oscillating circuit?
If I look at some of the other induction boards that are around, I see one that comes with a fan and has several extra pin inputs/outputs, but it seems to be impossible to find a schematic on any of these units.

 

[Gina1]

ottsm....

Ultimately, what are you trying to do? Lower cost, simpler build?

Gina

 

[ottsm]

Less interconnections, switching the high current DC with a relay is ok but the mosfets are already available to switch off the source. It is also easy to control with something like an arduino which can handle all the other automated functions as well.

 

[anri]

My annealer version works with SSR 40DD Solid State Relay from eBay for 5 USD. Arduino Nano board for 4 USD handle this relay just fine

 

[Gina1]

Very good... anri, ottsm.

As I have said, this is every one's build. improvements are always welcome. If your going to use an Arduino board, how about generating a schematic and posting the code to share. A parts list and parts source would also be helpful.

Being an old dinosaur in electronics, I used to work on old "tube" radio's and televisions I designed the "basic" annealer (with Hollywood''s help) to be "KISS" ( Keep It Simple Stupid). This way the folks on this thread/web site, with a little help from friends or other builder's could construct their own annealer.

Gina

 

[anri]

Gina, I need a bit time to prepare drawing, photo, demo video.

 

[Gina1]

Gina, I need a bit time to prepare drawing, photo, demo video.

I'm sure it will be interesting, and I look forward to seeing it. Anri, your not the first to use an Arduino board in one of these builds, but no one has pulled the curtain back to show the inner workings of their "Arduino" units. (wiring, parts, and coding). I'm sure if you get it all together and post it, you will ignite a new round of builders and more innovations.
So thanks in advance for sharing.

Gina

 

[anri]

Here is prototype level demo how I implemented Arduino based timer to handle solid state power relay.
Of course finalised solution will more serious with both Nano module terminal adapter board and wiring.

Here is video how it works.

Principial wiring attached.

Arduino code. Keep in mind I am not high level programmer. To read momentary switch state I am
using A0 analog input. Why not logical levels on digital inputs. I am waiting for touch sensor switch. in analog style I hope to control sensitivity Will see...
/////// code start ////////////
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
#define I2C_ADDR 0x27 // <<----- Add your address here. Find it from I2C Scanner
#define BACKLIGHT_PIN 3
#define En_pin 2
#define Rw_pin 1
#define Rs_pin 0
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7
LiquidCrystal_I2C lcd(I2C_ADDR, En_pin, Rw_pin, Rs_pin, D4_pin, D5_pin, D6_pin, D7_pin);
const int ssrPin = 7;

void setup()
{
//Serial.begin(9600);
lcd.begin (16, 2); // <<----- My LCD was 16x2
lcd.setBacklightPin(BACKLIGHT_PIN, POSITIVE);
lcd.setBacklight(HIGH);
lcd.home (); // go home
pinMode(ssrPin, OUTPUT);
//pinMode(indPin, OUTPUT);
digitalWrite(ssrPin, LOW);
delay(3000);
}

void loop()
{
int buttonValue = analogRead(A0);
int sensorValue = analogRead(A1);
float voltage = sensorValue * (10.23 / 1023.0);
int a = round(voltage * 10);
float newVoltage = a / 10.0;
lcd.setCursor(0, 0);
lcd.print(" Time: "); lcd.print(newVoltage, 1); lcd.print(" sec ");

if (buttonValue > 1010)
{
int b = newVoltage * 1000;
lcd.setCursor(0, 1); lcd.print(" ANNEALING... ");
digitalWrite(ssrPin, HIGH);
delay(b - 150); // 150 is correction number to get precise ON/OFF timing on pin
digitalWrite(ssrPin, LOW);
lcd.setCursor(0, 1); lcd.print(" DONE... ");
delay(2000);
lcd.setCursor(0, 1); lcd.print(" ");
}
else
{
digitalWrite(ssrPin, LOW);
}
delay(100);
}
///////// code end /////////////////

Part list:

SSR-40DD Manufacturer 40A solid state relay
http://www.ebay.com/itm/1Pcs-SSR-40...365085?hash=item4665025f9d:g:ccUAAOSwY3BZN2Zu

Nano V3.0 Mini USB ATmega328 5V 16M Micro-controller Board
http://www.ebay.com/itm/Nano-V3-0-M...876661?hash=item25b81fb8f5:g:RYYAAOSw5cNYfJ0j

IIC/I2C/TWI/SPI Serial Interface Board Module
http://www.ebay.com/itm/IIC-I2C-TWI...616356?hash=item258afcd8e4:g:nf0AAOSwZQRYgIMA

1602 16x2 Character LCD Display Module HD44780
http://www.ebay.com/itm/1602-162-16...320543&hash=item5d3be3eccd:g:uiMAAOSwZVlXkHXi

20K Ohm 3590S-2-203L Rotary Wirewound Precision Potentiometer Pot Multiturn
http://www.ebay.com/itm/20K-Ohm-359...645702&hash=item20ff065e9b:g:pX0AAOSwT6pVo4pt

Momentary switch
http://www.ebay.com/itm/Mini-Moment...846660&hash=item28364809fd:g:nQQAAOSw42dZMTmi

 

[anri]

... no one has pulled the curtain back to show the inner workings of their "Arduino" units. (wiring, parts, and coding).
Gina

This should be opened for everyone. And I want to say my BIG THANK YOU for this project. My shots extreme spread now is not more than 1-2 m/s most of times.

 

[Gina1]

Anri...

Thank you...

Gina

 

[Mike17]

Hi,

I've also started with an arduino version, because the "Sestos Digital Quartic Timer" arrived damaged twice.

Maybe this idea is also interesting for you. The arduino has enough I/Os ;-)

I ordered the following D/A-Converter (http://www.ebay.com/itm/MCP4725-I2C...le-12Bit-Resolution-2-7-5-5V-MQ-/112234541776) but I still wait for delivery.
=> https://learn.adafruit.com/mcp4725-12-bit-dac-tutorial/using-with-arduino
The plan is to control the reference voltage for the current limitation of the RPS-750-48 also via arduino.
This gives me the possiblity to store "profiles (times, current, ...)" for different types of cases.

With the DS18B20 Sensor I plan to add some temperature control.(http://www.ebay.com/itm/Waterproof-...-DS18B20-DS18B20-Arduino-Sensor-/291910128871)
=> https://create.arduino.cc/projecthu...digital-temperature-sensor-and-arduino-9cc806

I'm also still waiting for the SSR-40DD. Do you have tested if the induction heating board starts oscillating?

Mike17

 

[kit-808]

o wow guys, looks like my build may take a U turn

 

[ottsm]

If you want the I2C already built into the LCD I've been using this model for various projects;
http://www.robotshop.com/en/dfrobot-i2c-twi-lcd1602-module.html

Remember that the DS18B20 has a limited temperature range and will have a poll time if doing closed loop control. Also once adding additional sensors you will need to use the DS2482-100 which has the necessary slew circuit to go over long distances and have multiple sensors (I've had up to twenty on a network). They make thermocoupler amplifiers for the Arduino's analog inputs.

 

[anri]

I'm also still waiting for the SSR-40DD. Do you have tested if the induction heating board starts oscillating?

Mike17

Yes. My annealer is based on SSR-40DD. I bought several items, one of them was faulty.

 

[kit-808]

Just a little update


hope this works

 

[Gina1]

Just a little update

Sorry as posted image, unable to view