Machsupport Forum
Third party software and hardware support forums. => PoKeys => Topic started by: Chaz on October 09, 2017, 04:50:17 AM
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Hi,
Ive managed (after some struggling) to get my spindle to run. The issue I have however is that I seem to be limited to around 3.5V of reference voltage, irrespective of requesting full speed or not.
Not sure if its a config issue on my side or not.
How does the 57 USB board generate up to 10V with no external PSU? Can I somehow use the 10V terminal from the Chinese VFD if needed? I dont see a place to input this into the 57 U board.
Thanks
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Hi,
if its an open collector type output then yes you could use the 10V from the VFD.
Can you identify the type of output you're using? PoKeys seem to have several types of output, not all will do as you want simply.
Can you post the circuit diagram associated with the pin?
Craig
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Thanks, ill be home tonight and will map out what I have done.
I am taking PWM from pin 17 (red wire), going into the VFD's 'up to 10V' input.
Ground from the Pokeys goes into the VFD's 0V input.
If there is a better way to do this, I'm all ears, thanks.
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Hi,
I can't download a manual so I can't tell what pin 17 is. Can you either post the manual or tell me what type of output it is.
Craig
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Hi,
I can't download a manual so I can't tell what pin 17 is. Can you either post the manual or tell me what type of output it is.
Craig
Hi,
Its one of the PWM outputs.
(https://www.poscope.com/wp-content/uploads/2016/02/PoKeys57U_illustration_logo.png)
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Hi Chaz,
somewhere in the manual there will be a circuit diagram of the pin.
PoKeys seem to classify them as DO5, DIO33, OCOC etc. Any of them could be used but need to find out which one is used on this pin.
Craig
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Hi Chaz,
somewhere in the manual there will be a circuit diagram of the pin.
PoKeys seem to classify them as DO5, DIO33, OCOC etc. Any of them could be used but need to find out which one is used on this pin.
Craig
I looked, cant find it. I did a test and set the VFD to accept 0-5V, it now goes twice as fast but still not maxing out, doesnt matter what I try.
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Hi,
I suspect that the output is open collector, so with a 5k resistor and a 10V supply you'll be fine. An email to
Pokeys Tech support probably in order, they may of course see this thread and chime in.
I wouldn't hook anything up until I were sure however.
Craig
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So got a response early this morning. In effect, I have to build a 10V PSU setup. The board cant do it natively.
Im going to try RS485 via USB, seen that work before, so perhaps bypass the Pokeys completely for spindle reference. Pity, think the board works fairly well however this is a limitation for the board for the kinda stuff most CNC guys (and gals) need.
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Hi,
I've programmed my VFD to work with Modbus/RS485 in Mach4, it was a good programming/learning excerise but it offed NO
advantage over what I had been doing. I was helping someone else to program, as I say it was fun but otherwise a waste of time.
To modify what you have to work is very straight forward and MUCH MUCH easier than all that programming.
This is why I keep harping on about finding the circuit diagram for the output pin. This could be done with two pieces of wire and one 5 cent
resistor! Does that sound simple enuf. Depending on the circuit diagram you may have to add a transistor, another couple of resistors and maybe
a couple of capacitors if you want some filtering, total parts cost $2.50. If you cant or don't want to use the 10 supply on the VFD you may have to
buy a 5V-15V DC-DC converter for $10.....shock horror!
Could post a few circuit ideas if you wish. Sure would help if PoKeys would allow me to download the 57U manual or you could find that circuit
diagram.
Craig
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The manual is online, not sure why you are struggling to download it?
In terms of the circuit, they have shown one with a simple Op Amp. I agree, its not that difficult.
The RS485 way is fairly easy. I had a plugin before on Mach3 which worked fairly well where I used USB / RS485 - 2 wires going through to the VFD.
Ill try the RS485 adaptor tonight assuming its delivered today.
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As described in the support ticket, PoKeys57U is a general purpose I/O device that has support for CNC as one of its functions.
Pokeys57CNC was designed for CNC use and already has a 0-10V analog output built-in.
The manuals and software are always available under https://www.poscope.com/downloads/
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Hi,
the manual for the 57CNC is there and can download that but when I go to the 57U Related Downloads and try to download the manual listed
there (21.12.2016) I get a 404 error page not found.
All I really want to know is what type of output circuit is behind pin 17?
Craig
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Ill find a working link for the U board. Its all covered under the General document anyways. That said, I dont think it includes the level of detail you are talking about.
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Hi,
the 57CNC manual is very good, in fact its because of that manual that I know that several different output circuits are in use. It seems
very likely that the same circuits are inside the 57U as well and any indication as to which of the two or three output arrangements is used on
pin 17 and we'd be away.
Craig
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All pins of the PoKeys57U are listed in the PoKeys user manual - https://www.poscope.com/wp-content/uploads/downloads/Pokeys/Manuals/PoKeys%20user%20manual%20(19.8.2017).pdf (see pages 12-16). Electrical specifications table on page 21 provide all information you are looking for.
There is one type of pins in PoKeys57U and E devices - 3.3 V digital inputs and outputs that are 5 V tollerant for digital input signals (analog inputs still go 0-3.3V).
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Hi,
great, that link worked and very comprehensive manual.
Craig
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Managed to get it to work with RS485, cheap and cheerful solution. Now I just need to work out how to use pulleys / ratios via Mach 3.