VFD with 5i25 and 7i76

I am trying to get the forward and reverse output to work with my vfd. Currently in the hal file the spindle forward and reverse in set to

############## SPINDLE DIRECTION RELAYS ###################################
net spindle-forward motion.spindle-forward => hm2_5i25.0.7i76.0.0.output-00
net spindle-reverse motion.spindle-reverse => hm2_5i25.0.7i76.0.0.output-01

The problem with this is that I would have to use separate relays to make it work with the VFD. According to the 7i76 manual. There are

SPINDLE ISOLATED OUTPUTS
The 7I76 provides 2 isolated outputs for use for spindle direction control, and
spindle enable. These outputs are OPTO coupler Darlington transistors. They are all
isolated from one another so can be used for pull up or pull-down individually. They will
switch a maximum of 50 mA at 0 to 100 VDC. The SPINENA output is special as it uses
the same signal that enables the analog output. When the analog output is enabled, the
SPINENA OPTO output is on


How would I go about to change the hal file to get these outputs to work for my forward and direction signals.
I attached my files.

Thank you
Raul

You dont need relays if your VFD can use active high commands (these can connect directly to the field outputs)
if they are active low only, you can do this with a single SPDT relay by using the spindle enable and direction outputs:

VFD_Forward --> Relay NC contact
VFD_Reverse --> Relay NO contact
Relay COM --> 7I76SpindleEna+
7I76SpindleEna- --> GND
RelayCoil+ --> 24V
RelayCoil- --> 7I76SpindleDir+
7I76SpindleDir- --> GND

The relay needs a flyback diode for this use (Cathode to +24V side)

remartinez wrote: How would I go about to change the hal file to get these outputs to work for my forward and direction signals.

Unfortunately you can't have the analogue output active and the "enable" output false, they are controlled by the same pin in LinuxCNC HAL.

Many (probably most) VFDs can be configured for "ON" and "REV" rather than "FWD" and "REV". Have you checked if yours supports this configuration?

Hello,

just to ask, on mesa 7i76 card, what is the resistance of digital potentiometer between two end pins?
I want to connect to VFD, which recommended resistance of potentiometer is 2 - 10kOhm.

Have you tried just measuring it?

You should be able to read the component label, and find the datasheet.