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A couple things:

I missed your post about encoders

Whether encoders are muxed or not has no real effect
on configuration file setup or hardware setup.

Almost all mesa encoders (other than MPG encoders)
can be jumpered to select TTL or differential inputs.
This is true of the 7I76E and 7I85. Typically MPG inputs
are single ended, this means if you have a differential
output MPG, you only use the two  A,B lines and ignore
/A and /B

Typically 7I76E firmware with 7I85 or 7I85X puts the
first 4 encoders on the 7I85 or 7I85S
so that the sensible encoder/stepgen 0,1,2 = X,Y,Z
mapping can be used.

Also note that stepgen systems with encoder
feedback are rather complex and uncommon.
In fact, if you are setting up such a system,
its better to get a pure open loop stepgen
system configured and working before you
change over to encoder feedback

With pncconf if you setup encoder feedback
the hal file will have the proper connections
(feedback comes from the encoder)
 If setup without encoder feedback, the local
stepgen position feedback is used.

This may be pncconf version dependent
but current (2.9.2) does the right thing.

Note that tuning will be quite different
with stepgen feedback or encoder feedback
and with encoder feedback you must get
the stepgen scale and encoder scale  and directions
correct.



 

Hello,

First let me say I am a newbie and want to learn as much as I can from the wiser ones in this group.  Further,  I appreciate any and all help as I have been at this for over a year, on and off, trying to get my system working.  I purchased a 7i76E and 7i85 board from MESA and feel that there documentation (although very thorough but hard to digest) is, in parts, over my head .  MESA's support seems to be  lacking and that may be because I am not a programmer or a wizard at computers.  At this point in time, I would have not made the purchase knowing all the stress and time spent spinning my wheels. 

I have asked a question, recently, about MUXed encoders and grayed out areas of the pncconfig program with no reply.  Again its probably my fault because I asked the wrong question. Now I ran into another problem (one after another) concerning the "closedloop stepper signals" section of the HAL file (which I do  not know how it got in the HAL file, since I do not have a closed loop steppper). In any event, seems the pncconfig program wants to net the x-pos-fb signal to stepgen.00.position-fb.  This causes an error because I want the x-pos-fb signal to be connected to the x-axis encoder. In my logic (which is probably flawed)  the program should know that the x-axis encoder info should reflect the steppers pulse count and at the same time, verifying the ball screw movement. Very confusing on how this program logically looks at real world data.

Any help in clarifying what is meant by MUXed (MUX x 4 or MUX x 16) encoder vs a TTL or differential encoder would be appreciated.  I have TTL encoders and hope they will work with the above MESA cards. Also, I have a pendant control that has a MPG on it with x1, x10, x100  switch on it and will need help adding it to the HAL files.  The encoder on the Pendant seems to be differential as it has A+, A-, B+, B- wires.
In regards to the problem with x-pos-fb; I just commented out the lines where they were netted to stepgen position feedback .  Please, comment on this being the correct strategy.


Thanks,
ajc


 

@PCW
You need to set DI1 to RUN and DI2 to FWD/REV to work with the 7I76E
I think this is P3.01 = 1

From this list what should I be selecting based on your comment?  

 

forum.linuxcnc.org/27-driver-boards/3559...ethernet-mesa-boards
forum.linuxcnc.org/27-driver-boards

Attached is a zipped XLS copy of my setup sheet saved from Gsoft2, see any other problems?

The only other issue that I may have incorrect is parameter P03:20, P03:28 and P03:31.

The Durapulse manual is very helpful and written much better than offshore manuals but, there's a couple of places
in the manual that are a bit confusing. Especially this sentence regarding the braking resistor:

Set P06.01 to 0.0 to disable the over-voltage stall prevention function (connected with braking unit or braking resistor). Use this setting when braking units or braking resistors are connected to the drive.

The ability to program this VFD via software is priceless!

Yes, I have read about and I have installed a braking resistor that matches specs.

Additionally, I changed the ACC/DEC times from 10 secs to 12 secs.

The resistance of the cables in not important, the issue is most likely
EMI from the VFD. This may be improved with a common mode choke
(large ferrite bead) on the three wires going to the VFD. It also may be
that your voltmeter cannot read DC voltages accurately  in the presence
of large amounts of EMI

A USB/MODBUS adapter will likely also be susceptible to EMI so standard
EMI control measures may be needed in either case. These measures include line
filters on the incoming AC line power, common mode chokes on the interface
wiring and common mode chokes on the UVW motor wiring.

I tested my setup with cables as short as possible. Everything worked as expected. So the long cables are probably the culprit. Maybe capacity of the cables? or Resistence (0.2ohm)?

I ordered usb to modbus converters, hopefully they are more stable

you don't need a cross over cable.

Look at this, it may help.


P01.12 Acceleration Time 1 ♦R/W 010C 40269
P01.13 Deceleration Time 1 ♦R/W 010D 40270
P01.14 Acceleration Time 2 ♦R/W 010E 40271
P01.15 Deceleration Time 2 ♦R/W 010F 40272
P01.16 Acceleration Time 3 ♦R/W 0110 40273
P01.17 Deceleration Time 3 ♦R/W 0111 40274
P01.18 Acceleration Time 4 ♦R/W 0112 40275
P01.19 Deceleration Time 4 ♦R/W 0113 40276
P01.20 JOG Acceleration Time ♦R/W 0114 40277
P01.21 JOG Deceleration Time ♦R/W 0115 40278
Range/Units (Format: 16-bit unsigned) Default
P0145 = 0: 000–60000 sec
P0145 = 1: 00–60000 sec
1000 / 100
The acceleration time determines the time required for the AC motor drive to ramp from 0.00 Hz to
the maximum operation frequency (P01.00). The deceleration time determines the time required
for the AC motor drive to decelerate from the maximum operation frequency (P01.00) down to
0.00 Hz.
•
The acceleration and deceleration time are invalid when using P0144 Auto-acceleration and
Auto-deceleration Setting
•
Select the Acceleration/Deceleration Time 1, 2, 3, 4 with the multi-function input terminal settings
The defaults are Acceleration Time 1 and Deceleration Time 1
•
With the enabled torque limits and stall prevention functions, the actual acceleration and
deceleration time are longer than the above action time
•
Note that setting the acceleration and deceleration time too short may trigger the drive’s
protection function (P0603 Over-current Stall Prevention during Acceleration or P0601
Over-voltage Stall Prevention), and the actual acceleration and deceleration time are longer than
this setting
•
Note that setting the acceleration time too short may cause motor damage or trigger drive
protection due to over-current during the drive’s acceleration
•
Note that setting the deceleration time too short may cause motor damage or trigger drive
protection due to over-current during the drive’s deceleration or over-voltage
•
Use suitable braking resistors (refer to Appendix A: Accessories) to decelerate in a short time and
prevent over-voltage
•
When you enable P0124–P0127 (S-curve acceleration and deceleration begin and arrival time),
the actual acceleration and deceleration time are longer than the setting

Elo1 over voltage is normally caused by too fast of a decel ramp or lack of a breaking resistor.

Hi,

When I run pncconfig I get all the encoders pin types grayed out and read Muxed Enc 0, Muxed Enc 1, etc..
I cannot change it to Quad Enc A - Quad Enc B for each of the axis encoders I have.   The same is true for the StepGen which is also grayed on the pin type.  By the way I am using LinuxCNC 2.9.2.  Am I doing something wrong?  I have a 7i76e with a 7i85 card connected and used the discovery option in pncconfig and it picked up the card.  Also I chose 7i76 Mode2 I/O Card in the TB2/TB3 option.

Is there a jumper on the 7i85 card that needs to be in place to choose the type of encoders?
Thanks,
AC

If you get 1.2V on the spindle output  without LinuxCNC even running,
There either a wiring error or the 7I76E spindle output has been damaged
(most likely the OP-AMP U26)

gardenweazel wrote:

My spindle runs in reverse when the Durapulse VFD indicates Forward.

Change ONLY two of the motor wires.
Do unplug the VFD before doing this.

Hi,I have two boxes for my self-built CNC. One contains the Mesa card, stepper drivers, and 24V/36V power supplies, while the other contains the VFD. Both boxes are connected with a ~2m cable. I believe it is connected correctly. Spindle+ to 10V, Spindle Out to V11, and Spindle- to GND.Just by powering everything up, the spindle out reads roughly 1.2V, and if I start the spindle, it reads 8.1V. Also, the VFD shows ~20-40Hz in the off state and ~350-370Hz in the on state. That is obviously not what I want.

I tried setting 03.06 to 150 and 03.07 to 800, but that didn't help
 Did I miss something? Is the cable simply too long?