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Help required with wiring the Masso encoder for Sherline mill

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Hi Chaps

First a photo of where i'm at.

All four axes running, homing switches working,tool setter fine, soft limits done, Masso link sending files, just the Masso encoder to go.

A little background might help. Masso produce a kit for Sherline known as the Sherline/Masso cnc upgrade. If you order that kit  from Sherline you get a Masso unit built into a Sherline box

with everything that opens and shuts. All you need to do is follow Sherline's video instructions and plug this harness into here and that harness  into there.

However, I wanted to do it the hard way and order a Masso G3 and set it up myself.

When ordering this cnc upgrade kit from Sherline for an existing mill there is one mod you have to do yourself. This involves getting to the motor control pc board and removing the

potentiometer and the three wires attached to it. They are labeled on the pc board as P1 P2 and P3. You then fit three wires to the existing spades on the board, Red Black and White and lead them out of the motor enclosure for later use. And now for my questions:

  1. ) On the 5 point Masso plug which plugs straight into the encoder, there is an additional black wire which Sherline says to connect to the chassis of the mill. Failing to do this, they warn that on power up you will fry the encoder and possibly Masso as well. So my first question is where does this ground wire come from? Is it from Masso itself. Is it from the 24 v power supply or is it an earth wire from 220 v mains supply.
  2. )Second question>    In the Sherline setup video, once you have connected the "Black ground wire" and the 5 point Masso plug to the encoder, they say to connect the 3 wire power harness to the three wires that you brought out from the motor control pc board. Are these "power" wires from the Masso unit.....perhaps the spindle block ....are they from the power supply but that' s only two wires or heaven forbid are they  AC Live Neutral and Earth.
  3. Guys, I am too scared to try anything silly here and so I have simply left the encoder alone until I get some much needed advice. The encoder is mounted and a 5 wire harness is made up as per the Masso support page on the encoder ie A B Z 24v GRD. But nothing connected.
  4.  Perhaps some of you have access to the guys at Masso who produced this unit and understand the inner workings of the sherline DC motor and could enlighten us all as how to get this done
  5. Thank you all for your time
  6. Regards
  7. Andre
Uploaded files:
  • IMG_0452.JPG

Subsequent to placing this post, I received an email from Sherline direct which I think will throw more light on wiring the Masso encoder to the Sherline mill.

Their email reads as follows:

"The ground is from the units chassis…. Just makes sure both chassis are grounded together as to not cause a ground loop.

The voltage for the speed control is in the speed control unit itself…. The masso acts as the potentiometer only… it acts exactly like the knob it replaced."

Their Masso is enclosed in a metal box so i think the extra ground wire question is taken care of. My Masso is simply mounted on a board as in the photo above. However, I have a wire from GRD on the Masso to the chassis of the machine for the purpose of the tool setter....does this do the same thing to prevent a ground loop?

With regard to the second question of the Pot wires that I brought out from the motor PC board (P1 P2 and P3), which terminals do I connect to on the Masso spindle block...there are seven connections. Please bear in mind that this is a DC motor and we cannot run CCW

I would think our options are  Pin 1 (0 to 10v) , Pin 2 (motor direction clockwise/PWM output, Pin 4 (OPTO- motor direction clockwise/PWM output, and Pin 5 (OPTO-motor direction clockwise/PWM output

All other connections on the Masso block refer to CCW

Hope this gives you more to go on

Many thanks

Andre

@dup

Andre,

Finally read the Sherline installation PDF, so I can now give some answers to your questions. For a starter the Sherline/MASSO controller is a repackaged MASSO and we don't know what wiring arrangements Sherline have made inside their box.

Looking at their speed sensor cable they are using a DB9 to provide power (24v?) to encoder - 2 wires, encoder signal - 3 wires, leaving 4 wires for speed control and "ground".

  1. The extra black "ground" wire is connected to a MASSO "gnd" terminal.
  2. The "power" (RED & BLACK) wires more than likely go to MASSO power terminals and the white wire to the spindle pin 1 (0 - 10v signal), but I can't confirm this until we know what P1 P2 and P3 do on the speed control board. Can you supply photo of the board?
  3. Wire the Optical Encoder as per the MASSO wiring diagram, picking the power for the encoder from the power terminals on the MASSO.

This involves getting to the motor control pc board and removing the potentiometer and the three wires attached to it. They are labeled on the pc board as P1 P2 and P3. You then fit three wires to the existing spades on the board, Red Black and White and lead them out of the motor enclosure for later use.

The voltage for the speed control is in the speed control unit itself…. The masso acts as the potentiometer only… it acts exactly like the knob it replaced."

With regard to the second question of the Pot wires that I brought out from the motor PC board (P1 P2 and P3), which terminals do I connect to on the Masso spindle block...there are seven connections. I would think our options are  Pin 1 (0 to 10v) , Pin 2 (motor direction clockwise/PWM output, Pin 4 (OPTO- motor direction clockwise/PWM output, and Pin 5 (OPTO-motor direction clockwise/PWM output

As per 2 above just connect the white wire to pin1. That is assuming, white is connected to terminal that the wiper of the pot was connected to. SHERLINE could have a circuit that alters the MASSO 0 - 10v to a level the motor control expects and that is the reason that you have to "bring" out the power wires from the board.

However, I have a wire from GRD on the Masso to the chassis of the machine for the purpose of the tool setter....does this do the same thing to prevent a ground loop?

YES

Hope this helps.

Regards,

Arie.

Hello Arie

Thanks for coming back to me.

Just to recap the Sherline speed control has an on/off switch and pot to control speed before the conversion to Masso. The switch stays and the pot comes out.

Just to clarify the pot issue when I stripped it out....P2 went to the center tap on the pot and was white and P1 and P3 to the end taps.

If I reconnect the pot to the wires I brought out with P2  to center tap and  go to full revs on the motor by turning the pot fully clockwise, I measure a voltage on the one end tap of 8.25 volts and zero volts on the other end tap.

Here is a photo before I took it out:

 

In the photo the center tap has a white wire on it before removing the pot but there instruction when fitting the three wire harness you now have a red wire going to P2

The mail I did get from Sherline said that the Masso simply replaces the pot.

I have wired up the encoder exactly as Masso suggests and I am getting my highs and lows on the setup screen. Everything there looks normal. However, even though I am running the motor on the pot I would still have expected to see what revs it was doing on the Masso screen. Maybe that wont happen till we connect the three wires to the spindle block on Masso.

Another thing I noticed was that the sticker on the pulley in the Sherline video has only 5 black segments to it  whereas the one I got off the Masso page has 7 black segments on it. Not sure how this effects things.

Also note that they have a separate 3 wire harness (red white and black)  connected to the wires that I replaced the pot with, that goes down to the masso box.

I think these three wire would go to the spindle block on Masso

Arie, I hope this throws a bit more light on the issue and that you can come up with the answer

In the mean time, thanks for the help.

When this is sorted out, I will put a full wiring diagram up on the forum of how to connect your Sherline machine to Masso

It's strange, I have been running my HAAS machines for years and just take all this stuff for granted. But I have had a lot of fun setting this lot up. A big learning curve.

Cheers for now

Regards

Andre

Uploaded files:
  • IMG_0464.JPG

Andre,

I have big problem with the pot mod. If the voltage across the pot is 8.25v then the control signal is in that range, less than the 10v output from MASSO spindle control signal.

The fact that Sherline wants all three wires extended to their MASSO control box makes me think that they are doing something with MASSO's spindle control signal, because of this I'm reluctant to give you instructions for connecting the two together. So I think you need to contact Sherline again and explain that you are converting their mill without using their kit and could they supply a wiring diagram for connecting MASSO's spindle control signal to the Sherline spindle speed control board. Can't help any further here.

I have wired up the encoder exactly as Masso suggests and I am getting my highs and lows on the setup screen. Everything there looks normal. However, even though I am running the motor on the pot I would still have expected to see what revs it was doing on the Masso screen. Maybe that wont happen till we connect the three wires to the spindle block on Masso.

Have you setup the spindle on the F1 page, enter the number of pulses in the encoder box and set it to VFD, there maybe other values required but the documentation is not up to date with the actual requirements of the setup screen.

Regards,

Arie.

Thanks Arie, I'll keep you posted on any progress made here. Sherline seem reluctant to give specific intructions .  I think I know of someone who has bought the Sherline/Masso upgrade control box.

I will see if he will let me open it up and take a look inside.

Talk soon

Regards

Andre

Hi Arie,

I have more information now:

I spoke with Karl at Sherline again and here is his reply and I quote:

"Andre,

here is the DB9 pin out for the spindle speed control highlighted in red below

P3,P2,P1 refer to the connections on our spindle speed control board

DB9 (MALE) Connector on circuit board:

  1. P3 of the DC spindle motor drive (+ve of the KBLC Spindle Drive)
  2. P2 of the DC spindle motor drive (RPM of the KBLC Spindle Drive)
  3. P1 of the DC spindle motor drive (-ve of the KBLC Spindle Drive)
  4. 24v (output)
  5. Encoder A Signal (input)
  6. Encoder B Signal (input)
  7. Encoder Z Signal (input)
  8. Spindle CW relay (output) for relay coil
  9. 24v (output) for relay coil

We do not have  7 ports in the spindle block named"spindle". That block is on the stock masso unit sold by MASSO  (Karl attaches a photo of a standard MASSO G3)

we do not have a diagram of the traces from the DB9 pins to the connection on our masso board

(this might be something to request from MASSO)" End quote

I initially thought that there would be a stock standard G3 inside the Sherline control box. Here is a photo of whats in the box:

In order to find out what is going on here, I bought one from Sherline...I have it in front of me.

If you run it on a machine there is absolutely no difference in the functions, setup screen, masso link, optical encoder whatsoever...it is pure Masso in every instance.

The difference lies in the way it is put together....Top half and bottom half held together with about 12 male to female plugs. thus making the whole thing a lot smaller in length and breadth and slighly thinner than the G3

and circuit board top and bottom.

Now I can go ahead and pull this thing apart and separate top from bottom.

But another alternative is do what Karl from Sherline suggests.....ASK MASSO where to put the three wires P1 P2 andP3 which come from the KBLC (google it) motor speed control board.

Remember that Sherline uses the same 90 volt DC motor with the same KBLC board on every machine that they make.

So my initial question Ari, Before I strip this Sherline Masso down, is how do we ask Masso....I don't know anyone there and they simply say read the forum. I have scored the forum for two weeks now for eight hours a day but find nothing to show me the way. Suggestions, my friend?

What I have done in the meanwhile, is to take the motor to full revs (3000 RPM) using the SHERLINE/MASSO control and put a volt meter to the three wires in question.

With my +ve lead on red wire and negative lead on black wire, I am getting about 9.7 volts. stop the motor with M05 and all voltage is gone. Does this suggest red wire to pin 1 on spindle block (10v analog).

How does one get Masso to help us

Thanks for time and your patience

Regards

Andre

 

Uploaded files:
  • IMG_0484.JPG

Andre,

I think we are stuck with connecting the spindle speed control. From your description and the photo, MASSO has produced a OEM specific G3 unit for Sherline. My guess is that MASSO designed a opto interface for the speed control between the KBLC board and the MASSO unit. Reverse engineering the circuit that is connected to the DB9 pins 1-3 is one way to work out how MASSO provided the interface, the other is to ask them directly via the contact page or maybe Peter of CNCNUTZ has access to MASSO design department.

One thing I didn't see in Sherline's installation instructions was where the DB9 pins 8&9 were connected to, to provide CW switching.

As I stated in another message it has been about 25 years since I designed any electronic circuits, 40 years since I completed my diploma in electronics and there have been lots of changes in the electronics world since those days.

Regards,

Arie.

Hello Arie

I've been away for a few days,,,sorry for the late reply

Just want to say thank you for the help so far. I will try contacting Peter and see if can get some help from Masso

Will keep you posted once I get it right and put a complete schematic up for all the guys with Sherline machines

Best regards

Andre

NOTE: Please DO NOT connect the drive potentiometer wires directly to MASSO spindle output as it will damage the controller.

The SHERLINE drive is not designed for CNC interface, spindle drives such as VFD's are that are designed for CNC interface have special interface circuitry to take 0~10v signals for RPM control. The SHERLINE drive works on 110VAC and all electronics including the potentiometer connections have high voltages that can damage the controller and can also cause electrocution, so please do not open the drive box.

The SHERLINE MASSO box has special interface circuitry to control these drives, also as the drive is not linear, a special version of the MASSO software is used on the SHERLINE machines to adjust RPM via encoder feedback.

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