New Machine Build- How To Connect Spindle Encoder to EMC via Mesa?

[NICKKINSMAN]

I am running Mesa control boards for a Cadillac CNC controller new build. A 5I20 Anything I/O for the computer interface. It is fed from a 7I29 for x & z servo (including encoders), 7I37TA for limit swithes, start/stop, etc.

The only thing I need to hook up is the spindle encoder. It is a absolute type encoder with A, B, and Index channels. It has 5V+ and common. Somehow I need to get this terminated to get the feedback so EMC can know spindle location for threading.
I am thinking I may need another input board to terminate the spindle encoder too, but what kind? I can't find any boards specifically for encoders only, and all of them seem to be geared for axis control, by that I mean they have a servo power feed, and an encoder feed working together. I only need to get the encoder signal deciphered and back to EMC.

I am not 100% sure what type of encoder this is with the A, B and Index channels?

So, what I am asking is how do I get the encoder terminated back to EMC via the Mesa Anything I/O board? Someone must have done this in using Mesa boards on their lathe! Or, do I need something totally different to get this spindle encoder tied in?

I believe I need a board in between the encoder and Anything I/O that will power the 5V encoder, and decipher the channel signals to feedback to EMC.

Thanks for the help!

[Al_The_Man]

If the encoder is A B & Index, then it is a quadrature encoder, not absolute.
There are a couple of types of output, differential is considered the best as it has complements of each of the three signals, the other is just AB&I and this is either single ended push pull or open collector.
The other thing is the voltage, many especially diff. or P.P. are 5v.
Most motion cards accept differential but in some cases can be set for single ended.
It is common for controllers and drives to multiply the basic quadrature count and times it x4, so the resolution increases proportionately.
Al.

[acondit]

Have you used pncconf to generate a config for your lathe. It has setup in there for the spindle encoder. That should tell you which pins need to be connected to the 5i20 for the spindle encoder. I have a 7i43 with 7i42TA boards to break out the signals.

What are you using to actually connect the wires to the 5i20?

Alan

[NICKKINSMAN]

Yes, I have used PncConf to setup the system - I get that there are inputs needed at the 5i20 level. I know EMC has a section for spindle encoder, but I don't understand where it pulls its information from at the board termination level, and how to set it up to match my A, B, I inputs.

What I am trying to find out is what I need to use to actually connect the wires to the 5i20!

Right now from the 5i20, I have a 50pin cable to the 7i29 for servo X & Z, and 2nd 50pin cable to 7i37TA for inputs/outputs for spindle on/off, coolant, limit switches, etc.

I have no idea where to terminate the A, B, I, gnd and +5V wires from the spindle encoder!

[acondit]

It looks to me like you hook the encoders to the 7i29 (see page 5 of the 7i29 manual) then the 50 pin cable between the 7i29 and the 5i20 makes the connection to the 5i20.

Alan

[chester88]

If you used pncconf post the README from the config folder. It should tell you where the spindle encoder is expected to be hooked up.

But really you should know already. what connector tab was showing when you configured the spindle encoder? It corresponds to the connector number on the 5i20.
Is that the connector that the 7i37 is connected to?

if you are using EMC 2.4, What pin number is beside the encoder combo box that you picked for the spindle encoder?
The position of the combo boxes relates to the 5i20 connector.
The top left combo box is pin 1 on the connector , next combo box down is pin 3 and so on.

Hopefully that helps

[cncbasher]

you are using a BIT file which includes an encoder ?
that will give you the connection detail for the pins for A,B,I ( OR ABZ which is the same)
using the 7I37TA , using pncconf will set up the spindle configuration

you do not need any other connection interface , connect directly to the 7I42TA pins

[acondit]

NICKKINSMAN, Chester and CNCBasher,

The 7i29 has two connectors for the encoders to the attached servos. The manual says:

The 7I29 is a dual 22.5A 165V Hbridge intended for motion control applications when used with the MESA 4I27, 4I34M, 4I65, 4I68, 5I20, 5I22, 5I23, or 7I60 motion control cards. The 7I29 uses a 50 pin flat cable interface to the motion control card. The 7I29 is a 2 Axis card but can connect to 4 axis/cable FPGA controllers, allowing 2 7I29s to share a single flat cable from the controller. Motor power and motor connection are made with screw terminals. 10 pin encoder connectors allow TTL or differential encoders to be connected to the motion control system through the 7I29 card The 7I29 has overcurrent protection to prevent damage to the Hbridge from stalled or shorted motors. Each channel has two user selectable current limit values, full (22.5A) and low (11.25A) The 7I29s control circuitry is galvanically isolated from motor power and has 2500V RMS isolation for safety.

Alan

[cncbasher]

correct , but where is the confusion ?
servo card 7I29 is for x & z servo drives and axis encoders

the question was for Spindle rpm & spindle sync for screw cutting etc , this can connect to a 7I42TA .

[acondit]

I missed that Nick was only asking about the spindle encoder. In Nick's case the 7i37TA rather than the 7i42TA.

I wonder if his confusion is over which input pin on the 7i37TA matches which input pin on the 5i20? Or that the bitfile reconfigures gpio pins to encoder pins and the 7i37TA just routs the encoder signals back to the reconfigured input pins on the 5i20?

Alan

[acondit]

Nick,

Chester asked you to post the "README" generated by pncconf. It will show the pinouts that need to be connected to the 5i20. From that we should be able to help you with which encoder wires would go to which pins on your 7i37TA.

I am using a 7i43 so this does not directly apply but is merely an example of the info available in the "README" from pncconf. It shows that I need to connect:

pin# 7 (Pulse Width Gen-P) connected to signal:'s-pwm-pulse' pin# 9 (Pulse Width Gen-D) connected to signal:'s-pwm-dir' pin# 11 (Pulse Width Gen-E) connected to signal:'s-pwm-enable' pin# 14 (Quad Encoder-B) connected to signal:'s-encoder-b' pin# 15 (Quad Encoder-A) connected to signal:'s-encoder-a' pin# 17 (Quad Encoder-I) connected to signal:'s-encoder-i'

Alan

[NICKKINSMAN]

Thanks for weighing in everyone!

I did a little more experimenting today in PncConf.

I found that if I upped the encoder count from 2 to 3 in the Mesa board setup tab, that added the extra A, B & I pin selections (even says quatrature!) on the port 2 tab (ports 2, 3, & 4).

So, now under port 2 I have the x & z encoder pins used for the 1-25 pinout. And I have the 3 pins for the spindle encoder under the 25-50 pinout section.

Right now I have a 50 pin connector going to the 7I29 board which takes care of the 1-25 pins for x & z control & encoders.

I assume I need to jumper another 50 pin connector from the 7I29 to another board to pickup the 25-50 pins and grab that spindle encoder.

The question now is, what board does that jumper need to go to to provide the interface where I can terminate the encoder wires? Is it just a standard termination board, or is it something special which will take that encoder signal? Also, what supplies the 5V for the encoder?

Thanks for the help so far!

Nick