Automated 3 roller bender

Instead of "cascading" relays you may consider solid state relay (SSR) ..
Not only they provide full isolation between control circuit and load, but they can be driven directly from TTL/CMOS pins ( ) ..
You can build them of discrete components (Optocoupler, Triac ...) or you can buy them off-the -shelf, as one-, or three-phase devices ..
https://www.futurlec.com/RelSS.shtml

Regards,
IanP

How about using the relay listed below to work with the exsisting Motor Starters which have 120 volt coils? The maximum amps Roller 1 draws when it is pushing beyond it's limit is 7.5 amps, even though that mean the machine will burn if it doesn't stop. Working amps are between 0.25 - 4.0 amps. Can an additional component be added so the Roller 1 shuts off if it's being pushed beyond it working amps. A fuse or breaker would be inconvenient. It would be better if it just stopped pushing if it's going beyond it's working amps.

Another nice thing about these relays are that they only cost $1.15 each

Here is some info on relay
https://www.futurlec.com/Relays/JQC-21FF-12.shtml

Features
Pre-Tinned Leads
Contact Rating: 10A @ 240Vac/24Vdc
Electrical Life: >100,000 Operations at Rated Load


Specifications
Contact Data
Initial Contact Resistance Maximum: 100 milli-ohm (1A 6VDC)
Contact Material: Silver Alloy
Contact Rating (Res. Load): 10A 120VAC/24VDC
Max. Switching Voltage: 250VAC/30VDC
Max. Switching Current: 10A
Max. Switching Power: 2400VA/240W
UL/CUR Rating: 10A 120VAC
TÜV Rating: 5A 250VAC
Mechanical Life: 10,000,000 ops
Electrial Life: 10,000 ops

Characteristics
Initial Insulation Resistance: 100Mohm,500VDC
Dielectric Strength Between Coil and Contacts: 1500V,1min
Dielectric Strength Between Open Contacts: 750V,1 min
Operate Time (at nomi. Volt.): 10ms
Release Time (at nomi. Volt.): 5ms
Temperature Rise(at nomi. Volt.): Max. 60°C
Shock Resistance Functional: 98 m/s²(10g)
Shock Resistance Destructive: 980 m/s²(100g)
Vibration Resistance: 1.5mm,10-55 Hz
Humidity: 35-85%RH
Ambient Temperature:-40°C to +70°C
Termination: PCB
Unit Weight: Approx. 10g
Construction: Sealed & Unsealed


Coil
Coil Power: 360mW


Coil Data
Nominal Voltage: 12VDC
Pick-up Voltage: 9.00VDC
Drop-out Voltage: 1.2VDC
Max allowable Voltage: 14.4VDC(at 20°C)
Coil Resistance: 400 ± 10%

These relays should easily drive your motor starters, and they can be driven from a microcontroller pins through transistors .. see picture "RELAY5" at: ..

Regards,
IanP

**broken link removed**

I think these are perfect. The schematic stays as is, just use these relays.

Hi, VVV

I forwarded the schematic to www.digikey.com, tech department and they can't figure out the value for Q1. Can you please give me more info for Q1. I think that's the only thing missing before I order all the parts.

Q1 --> 4MHz crystal is pretty common for PICs ..
DIGIKEY shouldn't have problems in identifying this part; if you think you need to help them use this link:
**broken link removed**

Also, if I may suggest something, I would add some components around limit switches (see picture below) and 10µH-100µH RF choke between +5V and PIC's Vdd/C6 ..

Regards,
IanP

There does not seem to be any stock on 4MHz crystals, so try buying this 8MHz part instead: X100-ND

The TVS on the inputs are a good idea. You can buy these: P6KE6.8ADICT-ND
10k resistors: 10KQBK-ND
1k resistors: 1.0KH-ND
Transistors: P2N2222AOS-ND
Regulator: MC7805BTOS-ND
10uF cap: 565-2100-1-ND
1uF cap can be replaced with 10uF, to keep things simple, provided the input voltage is about 12V.
Buy a 10k pot that is rugged enough.
Don't forget the pickit 2. Perhaps you want to buy a spare PIC16F690, just in case.

Make sure you do not buy the relays shown on the schematic, those were just for reference. You will need a power supply for the relays, that is 12V. Is that voltage available?

I will update the schematic as soon as I have a little bit of time. I need to create a new symbol, too, for the PIC.

One more thing: in the case of resistors, caps, you may want to buy more than just the quantities required, just in case you need to make some changes.

I placed an order for all the parts listed with www.digikey.com. I added some parts that I could think of and a few extras . Here is a copy of everything I order.

For S1, I have a good micro switch with metal housing, its nice. I'm still looking for good proximity switches for S4 & S2. I already have several 12VDC transformers for relays and circuit board.

If I'm missing something, please let me know?

I have two questions:
1. What kind of device are you going to use for the alarm?
2. Is the 12V supply accurate enough to use with the relays?
Relays are very forgiving, of course, but the voltage should not be MUCH higher than 12V. For instance, I would not power the 12V relays from a 20V power supply. If that is the case, you may want to order a 12V regulator.

Added after 1 hours 42 minutes:

Here is the updated schematic. Please let me know if you find any problems or have any questions.
Note that the pins on the PIC are assigned in such a way so as to save for future projects based on the same part all the interesting features not used this time around: USART, SPI/I²C.
The pin driving the alarm relay can be used as a PWM and hence a direct buzzer output.

I will start coding now, but since I am very busy I don't think I will have anything before the end of next week.

1) Buzzer; 24VDC, .016 Amp, This thing is well built and very loud. I'm guessing I'm going to need a relay for this?
2) Max voltage on 12 Volt transformer is 14 Volts.
3) Is parts D6, D7, D8, D9; 15KEXX = P6KE6.8ADICT-ND?

How can I learn to program microcontrollers. Is there a book or learning kit that I can buy so that I can at least do basic stuff.

I think you can drive the buzzer directly with the transistor, no need for a relay, it's only 16mA. Does it need just a DC, or do you have to pulse the signal?

14V sounds OK to me to drive some relays, you do not need another regulator.

I did not check the exact parameters, but I think P6KE are equivalent to 15KE. Anyway, you can certainly use the P6KE TVS's.

The kit you are going to buy can be used for all kinds of development, using PIC16F690 (the one used for the bender machine), or PIC16F505, which can be used for projects requiring fewer I/Os (no A/D) and also 8-pin PICs, PIC12C508/9, or PIC12F50x (my favourites). One of these can be used to do your first project. Too bad I did not mention it, you could have ordered it from DigiKey with the rest of the stuff, it's only about $1.
You should save the board that comes with the pickit 2 and build your own PCB for the project(s).

As for learning, the Microchip website has lots of appnotes on different things and there are some books on programming the PIC. You can search this board for some info, too.
Here is a link; the book I would consider is "Assembly for PIC Microcontrollers".
http://www.ucpros.com/Resources/books_microchip_pic.htm

I found that the best way to learn is to do a project.
My advice is that you try to do the first project using a PIC12F508, which you can actually program with your kit.

Once you have done that, you can use any other PIC, they just add more features (and the memory is organized differently, but that is manageable).
You can start by downloading and installing the MPLAB IDE software from Microchip (actually you may receive it with your kit). It contains editor, assembler, simulator.

Sorry but I made a typo. Buzzer is 0.16amps.

I connected the buzzer straight to a DC transformer and it worked good. I don't think we need to pulse the signal

I'll be receiving all the parts on the 21st. I can't wait to starting putting this together.

I wouldn't expect project like this to work correctly from the very first time ..
There will be some commissioning involved and it would be very beneficial to you if you learned as much as possible about microcontrller(s) you are going to use ..
Here is another publication on PICs:
"PIC microcontrollers, for beginners too .. on-line, FREE!
PIC microcontrollers : low-cost computers-in-a-chip; they allow electronics designers and hobbyists add intelligence and functions that mimic big computers for almost any electronic product or project. The purpose of this book is not to make a microcontroller expert out of you, but to make you equal to those who had someone to go to for their answers. Book contains many practical examples, complete assembler instruction set, appendix on MPLAB program package and more... "
**broken link removed**

Regards,
IanP

Here is the first version of the code. Unzip all files and then open the project file (click on the GREEN open file icon in MPLAB).
Please read my comments carefully. The code is written in such a way as to familiarize you with the chip and allow you to reuse much of it for other projects, possibly based on 12F50x, or 16F505. Therefore, I am not using any interrupts, nor more than 2 nested subroutines.

Remember, there are many things that can go wrong and code rarely works (if ever) as expected the first time around. But you need to give me some feedback and comment on all strange behaviour (bugs), as well as clarify possible timing issues. So if the code does not run as expected or not at all, do not panic! All bugs can be fixed (as long as they are detected).

I assumed that all the sensors will be debounced using 20ms and I assumed that 100ms should be sufficient for the relays to disengage. But will the motors stop within that time? If not, how much do they need?

Please review carefully and try testing it WITHOUT CONNECTING ANYTHING TO THE MACHINE! You can hook up a few switches and relays and simulate the inputs and look at the outputs and see if that is the desired operation.
I will wait for comments.

I had purchased an electronic learning lab awhile back and have used it to test this circuit. It has a lot of features that I found useful.

Please disregard my old post. I made errors when I assembled the circuit board together. I'm going to check my work throughly before I make another comment.