7i95T spindle control via Modbus RS485 and SPINX1A

Hi guys, 
As my lathe drives are now with step dir, I decided to replace my 7i97 with a 7i95T. The problem is that the new board does not have analog outputs and I will have to command two vfd's.

• spindle vfd - I wanna command this over modbus RS485, using one of the 7i95T serial ports (now I was using AOUT+-, ENA+, ENA-, do I still need to send the enable signal to the VFD if I use modbus)
• toolpost grinder vfd - using the SPINX1A acting like a potentiometer. Here I'm hoping to use one of the step dir outputs as an input for this board

I will use both serial ports, on the other port I have a 48 inputs card. 
I understood that I need to write a custom bit file in order to be able to use modbus via mesa serial ports
How can I get the custom firmware for this?

Thanks, 
Vasi Mihalca

There's existing firmware with a UART on one serial port:
7i95t_1pktv2d.bin, but it sounds like you need 1 PWMgen also
so that would require custom firmware. I can make this firmware
sometime this week when I get a chance

Note that the mesa-modbus support is basically experimental
at this point and does have some known bugs.

Can I use that PWM Gen from one of the 6 step dir outputs or is it mandatory to use the expansion port. Can I have two SPINX1A in case mesa modbus is not stable enough for me?

Yes, the PWMgen outputs can be either step/dir TB pins or the expansion port

When you make the firmware, can you make it so that the last two step dir ports have pwm support. I case I don’t like how modbus works, I can use two SPINX boards for my vfd’s

Regarding modbus, is this UART stuff noise imune? Is this approach with modbus controllable with mb2hal?
I have zero experience with modbus so far, but I would want to be able to read some status like torque and power consumption.

 

7I95T configuration with 1 sserial, 1 PktUART, and 2 PWMgens
on step/dir channels 4/5. I have left the PWM dir pins as GPIO
in case you want to use them for enable or some other function
instead of direction.