Mesa Cards choice

Hello,

i am planning on building a small 5 Axis CNC and wanted to ask if my Mesa configuration is going to work. It is going to use 7 Servo motors, 5 for Axes X,Y,Z,B,C then the Spindle and the last one is the Toolchanger Motor (Chain Type Toolchanger). All servos are getting Encoders with A and B signal except the Spindle, which has Index or Z signal for Rigid tapping or Spindle orient. Servo drivers i am going to use Tarocco Servo driver for all axes (with custom Software) and control them just with 5V PWM and Dir signal. The encoders (XYZ Glass scales, B and C magnet encoder, each 0.001mm and ° resolution) go directly into the Mesa card (my maybe configuration is on the bottom of this post). I want to add two potentiometers for spindle and feed override, Buttons for X+ X- Y+ Y- Z+ Z- B+ B- C+ C- and a Rapid button, Mist and Flood Button and Spindle release button. On XYZB axis i am going to use Limit switches and Reference switches, on C axis only reference switch. The spindle is going to have two buttons to see if the tool is released or stuck. Also some other things i forgot. If i summed all pins correctly, i might need at least 69 Pins so the 72 Pin 5i20 may work but what if i need more pins?

Mesa cards:

5i22-1
7i52
7i37
7i73

thanks for helping

A 5I25 and 2 7I85S's would give you
8 encoder inputs all with index
8 PWM/DIR pairs (differential if needed)
2 sserial expansion ports

If you added 1 7I84 (connected to 1 of the 7I85S's sserial expansion ports)
this would add
32 12/24V inputs
16 12/24V outputs

4 of the 7I84 inputs can be used and analog in
another 4 can be used to support 2 MPGs

thanks, i will have a look

basically one 7i85s goes in the front connector and the other in the back connector?

Yes
( theres a cable/bracket adapter if you need to get the 5I25s internal header wired outside the PC case )

Okay i quickly compared the Configs with Pncconf and found out that there was no 5i25 and 7i85sx2 firmware, so i googled and found out i have to manually download a software package from the Mesa website and copy it to the hm2 directory, so i did that and found the config for 5i25. The thing is, i cannot generate PWMgen with 5i25, only stepgens, with the 5i22 i can do that easily but when i open the input/output connector 5, all pins are just white and i cannot add anything to them. It seems like i can generate the machine way easier with th 5i22 than the 5i25 but it is more expensive. I may do screenshots tomorrow

The 5i25 config for encoders/pwmgens is 5i25_7i85spx2.bit, but
I dont think pncconf will help with your configuration very much
regardless of what FPGA card is used

okay i will have to see,

out of curiosity, does homing on index signal work good? Especially if the Glass scale has a resolution of 0.001mm? What if the index signal is somewhere in the middle of the scale, does linuxcnc reverse the direction when it hit the limit switches?

3D-Master wrote:

okay i will have to see,

out of curiosity, does homing on index signal work good? Especially if the Glass scale has a resolution of 0.001mm? What if the index signal is somewhere in the middle of the scale, does linuxcnc reverse the direction when it hit the limit switches?

Homing to the index pulse is more accurate, in most cases, it can index to an exact encoder count. With .001mm scale resolution, you might have to make the HOME_LATCH_VEL pretty slow to be sure the exact count is always registered.

There are many options to the homing sequence, so it can approach the home switch fast, back off, then trip the home switch slowly and then continue in the same direction to find the index pulse, or back away from the home switch to find index.
This is all done with the arithmetic signs of HOME_SEARCH_VEL and HOME_LATCH_VEL.

Jon

okay thank you, but what i ment was if the Index signal is somewhere in the middle of the Glass scale and the machine starts homing in the wrong direction (away from the index point), does Linuxcnc reverse the homing direction if it triggers the Endstop Switch?

i just found the 7I80HD, which has 72 Pins but is connected to the PC via Ethernet. Is Ethernet now as good as normal PCI cards like the 5i20? If yes i may go with the 7i80HD