[Jakar]

I have been retrofitting an old Emco F1 mill. Ewerything is working fine except the spindle speed control. I run Mach3 which controlls the Leadshines Mx3660 controller. I have configured ewerything in mach3 ( the controller needs the pwm signal at pin 14). The controller is connected to the old motor control board of the Emco which previously had a potentiometer wired to it but I replaced that with the analog output of the controller.Attachment 238064Attachment 238066Attachment 238068Attachment 238070
The motor control board (without the potentiometer and the controller) just kept speeding up the spindle until it reached top speed. When I connected the input wire with ground it slowed down. I have no idea what is wrong and why it doesnt work. When I turn on the relay that supplies the control board the spindle starts to turn but it runs on the minimum setting And changing anything in Mach3 doesnt affect anything. So I guess that something is wired wrong?

[cgo]

First I would like to say, I dont have any of the parts your using and Im only going by the pictures in your post.

You will need a volt meter to test the "fia 112000" boards three terminals.

The pin at the top of the pot in your first picture, should be the wiper pin ( 0-10 volt ) , the other two pins will need there voltage measured to find the +10 and ground.

A place on the fia board to ground your volt meter for testing maybe the blue capacitor by the label "fia 112000. Look at the value of the capacitor, it should be under 25 volt in rating and be on the low voltage side of the board, remember about half that board is tied to mains when its powered up, so if you are comfortable with working on electrical circuits with power on and know how to safely, then you can do this.

In your other pictures you have a black wire tied to what should be the 0-10v and its going to ground on the bob in your picture, which would make the motor run slow or not at all (from what I can tell in your pictures).
There is no way to know if the other two wires are the ground or +10 volts without first testing the voltages from the fia board, which could also be 5 volts control and not 10 volt. This being wrong could have already damaged the speed control and or the bob in the worst case.

One last thing is, because the fia board had a pot, you may only need to use the ground and the 0-10 volt connections to adapt it to your new "bob" (if it did use 10 volts), if its 5 volt you will need some type of voltage dividing circuit between the bob and fia on the 0-10 volt wire.
Check your voltage first is you best option.

If you still have problems then:
An easy test for the fia speed control would be to hook it back up the way it was before you started and see if it still works.
A test for the bob would be, while disconnected from the fia controller, measure the bob output from 0-10 and ground , while changing it in mach, seeing it also goes from 0-10 volts.

[cncfixxer]

Sounds like you have the "wiper" on the wrong terminal or the pot has opened

[Jakar]

We measured the outputs of the motor control board (fia 112000) and the wiring should be correct. the red wire is conected to the +10V output from the board (fia 112000) and the black wire should be ground. I will try to check and change the yellow and black wire to see if id changes anything.

[Jakar]

The wiring is correct the +10V is the red wire the yellow wire is 0-10V and the black is ground. I changed the ground and the wiper and nothing happened. So I changed it back. When I measure the voltage between the +10 and ground and the voltage was 1.3 V. When i measured the voltage that came out of the analog output from the controller the voltage was 0.2 V. Maybe there is current shortage?

[cgo]

This is a very simple drawing of what is inside the fia control, the LM324 ic runs from about 12 volts (vcc pin 4) and in the fia it uses a scr(s) not a mosfet, but the LM324 wiring part is probably very close.
As you can see the wiper lead on the pot is your adjustment between the power supply rails which are not exactly + and - . The fia control runs a motor probably 90 or 180-220 volt dc guessing thats why I say scr outputs.
It does not need the +10volt off the leadside directly because it already has a power source and was not designed to be adjustable through a bob, it uses the pot as part of its wiring. In order to make it work will require an additional circuit between the bob and fia, which would be just a few extra parts.

Pulse Width Modulation
In this drawing you will see VR1 as the speed pot, Q1 is a mosfet running from about 12 volts to control the fan motor in there picture, this is the part that doesnt match your fia which uses a SCR at a much higher voltage. If you want to understand the basic operation of the fia control you should read about the LM324 IC on the link I added.

The Leadshine was designed to run VFD which already has an input for 0-10 volts and may also require a 10 volt+ bias voltage.

The black wire is the control wire (what would be 0-10v) coming from the fia, you should be able to trace it back to one of the +pins on the LM324 IC ( pin 3,5,10 or 12 ) can be the + in pin on that quad IC.

This setup will probably not directly control the fia without some type of additional circuit.

[Jakar]

Thank you for your quick response this is very helpful. I will try to get this together and will post it here as soon i get it done.

[Jakar]

Okay so I have to make an analog pot? What would be the additional circuit?

[Jakar]

So I guess i have to build something like this?
Digital Pots Achieve Voltage-to-Resistance Conversion - Application Note - Maxim
If Im correct this should solve the problem.

[cgo]

One of the lm324 amps is used as a comparator which is the one hooked into the speed pot, you are adjusting a small voltage change to control the pwm. In the link I gave they used U1D which is pin 12.

This is what I did with a LM339 (quad amp but different pinout) which is very close to the LM324.
It maybe as easy as adding two resistors in series on the fia, and using the center of the two for your 0-10v connection and the wiper of the pot, the other two ends would goto the fia pot gnd (bob gnd too) and fia pot+ leads. I would leave the +10 on the bob unhooked.

I would try measuring the pot , then using that to determine the value of the two resistors, if its a 100k ohm for example, then try maybe 10k and 90k to make,
gnd fia and bob <>90k <> center (0-10v and fia wiper) <> 10k <> fia + lead.
At 10/90 the motor may not run and thats what you want with no signal coming from the bob. This is safe to try once you find the value of the pot but I am only giving it as an example untested, its upto you if you want to try it and also fine tune the values to make it work.

Depending on the output of the bob you may also need an inverting stage between the fia wiper wire and bob 0-10v, on the lm324 as the voltage goes lower on the control, makes the motor go faster. (maybe can use a setting in mach to reverse the voltage, low=high/ high=low on the bob 0-10v output ?)

I see theres another pot on the board by the wires which maybe a high speed limit pot or a low set maybe. Tracing it should tell you.

[Jakar]

The bob (Leadshine mx3660) requires a seperate power supply for the analog output (+10V is an input) to function. 0-10V is the output. When I supply the analog output with 10V the 0-10V output functions correctly (when I want more revs it puts out bigger voltage).The FIAs speed control pot is 100k ohm.

[cgo]

Ive looked at your pictures again, can you tell me what pin on the lm324 the black wire is hooked to ?
If it goes to one of these (2,6,9 or 13) then your in luck.

[Jakar]

I will check tommorow. And what if it is connected to one of those pins? what can I do then?

[cgo]

Based off your pictures and looking over the link drawing, I am thinking now that the fia is using the inverting input for the control pot, which it can.
That would make it so the pot would go + in voltage to raise the motor speed, the opposite of that drawing the way it is setup , it goes - to make the motor go faster.
If this is true then , it will be alot easier to connect it to the leadshine bob , which is also a + signal.

This is a rough idea but you could try it now if you want.
You will need to test this part first, using a 10k and 90k resistor in series, connect to the fia only for this test. yellow {10k} black {90k} red
The resistors are not critical so 10k and a 91k(common value) will work, 1/8 or 1/4 watt is all you need for these two resistors.
The motor should still be off (what you want) or maybe humming or running very slow at worst case when powered on.

This would be the lucky part, making it easy to hookup to the leadshine.
What this would be is a bias voltage for the fia board / lm324 ic.

[Jakar]

Ok so the black wire isnt connected to any of the pins on any of the two chips. The yellow wire is connected to pin 3 on the bottom chip.

[cgo]

Ok so the black wire isnt connected to any of the pins on any of the two chips. The yellow wire is connected to pin 3 on the bottom chip.

Ok I will ignore your first picture then, the one with the control pot in it.

black {10k} yellow {90k} red

This will probablly make the motor run almost full speed ( because it goes to pin 3) , will need tested though.