Reply with QuoteReference to ground. MUCH appreciatted. I'm banging my head against a wall and botherring these nice people about it as well:Originally Posted by N4NV
http://forum.allaboutcircuits.com/sh...ad.php?t=19296
Thanks for the help!!
Mark [mkenney]
With reference to ground or +VCC? I will bench test it today. OK, I just tested it. With an input voltage of 5.27V, between the output pin and ground I get .512V with no magent and .008V with the magnet. This switch is a current switch not like a regular mechanical switch. The voltage does not mean much. When the switch closes, it allows current to flow, so the reading of .022 looks correct for you. Think of it as reading across a mechanical switch, when it is closed you will not see any voltage. I still don't fully understand these solid state switches, but as long as they work, I don't try to. The change in voltage you are seeing tells me your switch is working.
Depending on the break out board you use and how their logic is wired, it could take from no resistor across the output to +VCC to 10K and just about anything in between. The resistor is to provide a voltage drop across it when the switch allows current to flow so the BOB can see a voltage at the pin.
Vince
Last edited by N4NV; 02-15-2009 at 10:53 AM.
Reference to ground. MUCH appreciatted. I'm banging my head against a wall and botherring these nice people about it as well:
http://forum.allaboutcircuits.com/sh...ad.php?t=19296
Thanks for the help!!
Mark [mkenney]
Thanks for the input, sorry for the late reply.
Well that makes a lot better sense now, my C10 board from CNC4PC must just not switch at the right point or something for this sensor? I tried lots of different pullup resitors and either got off (low) or on (high) all the time. Usually when I did get to high I would discover that I had cooked the sensor at the same time:-( So frustrating as I just love this idea so much and can't seem to get it to work. Any suggestions on a next step?
Thanks again for taking the time to measure your's!!
Mark [mkenney]
That device you show is open collector with a current capable of 50ma, so at 5v, the Min. resistance that can be used from output to 5v would be 100ohms.
Normally with an open collector device, when it is off there should be close to 5v on the output (collector) and very low voltage, <.5 volts, when on.
You only need a pull up if the circuit it is connected to does not provide a resistive path to 5v.
This device is called a sinking device and the BOB would be termed source.
It is important, especially when using this type of device to know the exact nature of the BOB input.
The voltages I mention are WRT common, or ground as I believe they use on that BOB.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Probably not what needed but here are the specs on the digital input:
On-State: 2 to 5V DC
Min on-state input current: 1.1mA
Max off-state voltage: .8V
Max off-state current: 1.1mA
Do these figures give me something to go off to make this work for this board somehow?
Mark [mkenney]
To me those figures look like they would almost be from a sink type input?
What voltage do you get on an input when the switch is not connected?
Why they do not show the input diagramatically is beyond me.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
I may be answerring the wrong question. When I test the inputs on the BOB itself, they are all ground without anything connected. If you apply 5V to them they trigger as on then. Anywhere close to what you asked?
Mark [mkenney]
If that is so, they are not ideally suited to a NPN sink device that your hall effect is.
Some one somewhere has probabally reverse engineered the input to show exactly what the input configuration is.
To feed 5v into them with a solid state device such as you are using, it would have to be a source type, PNP etc.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
If the input is the way I think, one way may be to use the hall effect in reverse logic, similar to a normally closed switch.
To do this, with the hall effect disconnected, find out what the lowest resistor from 5v to input will turn on the input, try 500ohms and no lower than 150ohms.
When the input turns on, connect the hall effect, now it should work except reverse logic, when the hall effect is on, the input will be off, and vice-versa.
What happens is, the hall effect will force the input to common or off.
Not the best solution, but it should work.
Al.
Last edited by Al_The_Man; 02-16-2009 at 10:00 AM.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Mark, are you sure the input to the BOB your are using is working? I went through a similar problem with my C11G board trying to get my spindle sensor working on my lathe. It turned out that the pin 11 input was not working on the BOB. Try some other inputs. I also found that the PMDX-122 BOB works great with these hall sensors without any resistors but you do have to reverse the logic in the software.
Vince
Last edited by N4NV; 02-16-2009 at 12:02 PM.
Looking at the manual, it appears it can be set for sink or source by jumper, http://cnc4pc.com/Tech_Docs/C11GR7_1_User_Manual.pdf
This also show the PNP or NPN requirements.
I suspect the problem it is it set for source input devices instead of sink device.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Wow, I think you can hit me in the head now! The NPN p[en collector sensor diagrams show a 12 or 24 volt external power supply being used with them. I don't have one of these connected, just the 5 Volt from the board. Vince is able to get away without this, but mine must want it???
Sound about right??
Mark [mkenney]
All my sensors are working at 5V (there are three of them). On my mill I have the CNC4PC C1 board. I am going to change to a PMDX 122 board as soon as my speed control board gets here from Peter Homann.
Vince
I think this new sensor is going to work with my board. 4.5 Volts on and close to Zero when off. Can't wait to try it off the breadboard and interfacing the BOB itself... Attaching the datasheet on it...
Mark [mkenney]
What was the cost on these? Never mind, I just checked DigiKey and they have them in stock for $7.22 for 1, $4.16 each in quantities of 100. No a bad price for a sensor that is already mounted. That would have saved me a couple of hours on some of my installs. I might have to order some and check them out.
Vince
Last edited by N4NV; 02-22-2009 at 12:07 AM.
They are $7.22 with the part# 55100-3H-02-A-ND. I'm hoping to get some time today to try it out!!
Mark [mkenney]
Fixed! Someone pointed out that the pinout is different on the UA package but that the SOT-23 package is listed first in the table and confusing. The pins should be:
1- Vcc
2- Ground
3- Output
So i had the Ground and output pins reversed!!
Works like a charm now with over 4.5volts without a magnet and close to zero with a magnet next to it!!
Mark [mkenney]
I made the same mistake when I fist wired them as well.
Vince
noob question on these hall switches
I got some of these switches from digikey and without using the 1k pullup resister, with 5v going in I get a .60v normally and almost 0v when the switch is triggered. Should this be right? By adding the 1k pullup it should bring it to 5v?
Second question if I am correct would it be ok to wire the 1k pullup off the 5v Vcc input directly to the hall voltage output so I'm not sending .6v signals all the way to my control?
thanks
Yamazen Retrofit
I'm very impressed with your retrofit, I hope I'm not hijacking this thread, but I have a Topwell 5BVK ( a sister casting to your yamazen) that was "decomissioned" before I bought it. It has the ballscrews , but no quill pinion, control or actuators (servo/stepper) or spindle motor. I believe it was originally equipped with Anilam control, but I can't be sure. It was built in 1996. I don't have any idea what size servos came with my machine, and I'm doing a single phase-three backyard retrofit myself. I'm wondering if you could share your experience and provide a breakdown of the parts you used to bring your to life. I appreciate the time you have invested, and understand if you want to keep some things confidential, but I would like some guidance so I buy well suited components. This machine is somewhat elusive with regards to specifics about the original cnc control, I do however have a thorough user/parts manual. I'm very green with regards to CNC construction, but I do have CNC machinist training. I'm curious to know if the servos are driven by in line amplifiers or directly off the gecko drive? Are the encoders integral of the servos, and if so what is their resolution? Thanks, excuse my ignorance.
