Main > Main Forum
Electrical Wiring Question (Update: IT WORKS!!!!!)
DaOld Man:
You should be concerned with how much current the counter draws.
I would be afraid that it would be too much for the Ipac.
You can hook an amp meter to it and see how much it draws.
I would say that more than 20-50 ma might be dangerous for the Ipac, but I really dont know.
Im not sure how much the keywiz can source. i asked randy of GGG once but I dont think he ever answered it.
If you use opto isloators, or at least transistors, you should be ok.
Opto isolators are very small, and very easy to hook up. (4 connections)
Just consider them as a normally open relay. But they are limited to how much current they can switch.
DaOld Man:
Here is another way you can do it.
This uses the same diode arrangement to turn on the counter as yours.
im using 2 opto isolators to switch the encoder inputs.
Im not showing the surge diode on the counter, since yours has one built in.
Jdurg:
Yeah. I'm using a Kessler-Ellis KE610AF model counter rated at 4.5/6V DC and 2 Watts, so with the good old Amps x Volts = Watts, we have something on the order of 2.25/3 amps which is well above the specs you put there. I guess I'll just need to do something to reduce the current. Thanks for all the help by the way. :cheers:
Oh yeah. As a side note, the power supply would only be providing power to the counter and is not going to be providing power to the encoder. So the only connection in the entire circuit to the power supply is the +5V connection. Is that going to work, or will I somehow need to connect the negative from the power supply cable? Ugggh. I can't believe I completely ignored the negative terminal from the power supply. (Though it's actually a ground from the power supply feed).
DaOld Man:
Actually the formula to find amps is watts/volts
So
2 watts / 4.5 volts =0.44 amps (or 440 MA)
Or if you use a 5vdc power supply:
2 watts / 5 volts =0.40 amps or 400 ma
The second drawing, using the opto isolators to trigger the encoder inputs should work very well.
I would not switch the counter with the opto isolators like I show in my first drawing. it may overload the optos.
The coin switches should be good for at least a couple of amps.
You will need to use 1 amp diodes.
also the resistors for the opto isolators need to be around 200 ohms, not 330 as I originally posted.
If you do something to reduce the current, you will reduce the voltage too.
If you get much below the 4.5 volt rating, you may harm the counter, or it may not work properly.
With the currents you are looking at, i dont think i would feed the ground or the pos for the counter through the encoder.
But if you go with your first drawing, you will need to tie the ground of the power supply with the ground of the encoder, since the coin switches are breaking the ground.
Good luck, and keep us posted..
Ed_McCarron:
--- Quote from: DaOld Man on March 24, 2008, 10:06:12 am ---You should be concerned with how much current the counter draws.
I would be afraid that it would be too much for the Ipac.
--- End quote ---
Wha?
In Jdurg's schematic #2 way up there, the IPAC input sits at 5v, most likely via a pull up resistor. The (-) side of the counter will be at 5v when idle, so no current at all will flow.
When the switch is triggered, both will be pulled to ground. No current will flow from the ipac other than what would normally flow when you ground it's input.
Unless i'm missing something (which is very possible) the optoisolators seem like overkill - unless you are worried about the inductive kick from the coil field in the counter collapsing - which can be handled by the reverse biased diode shown later.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version