Thanks. Unfortunately, it doesn't quite work. The DMC-18x2 manual says.
For each axis, the SM jumper selects the SM magnitude mode for servo motors or selects stepper motors. If you are using stepper motors, SM must always be jumpered. The Analog command is not valid with SM jumpered.
According to Galil Support, The SM jumper doesn't apply an absolute value function to the output (e.g. like a diode bridge). It compresses the -10V to +10V into 0 to 10V, with 5V as the center. Max reverse RPM would be 0V, max forward would be +10V, and 0 RPM would be 5V, and that assumes the analog output even works - which according to the manual it does not ("The analog command is not valid with SM jumpered.").
I'm assuming the Mach3 Galil driver is using OF (offset) commands to output 10V for max forward spindle motion, and -10V for max reverse spindle motion. What I need is to always get 0 to +10V regardless of spindle direction (0V = spindle stopped, +10V = spindle max RPM).
A diode bridge sort of works, but issues with the diode drop are problematic. Besides I hate to use electronics to do what software should be able to do much easier.
In this forum post (
http://www.machsupport.com/forum/index.php/topic,12652.0.html) from Sept 2009, Smuph suggests that more such options need to be added to the Galil driver to make this kind of spindle control possible. I'm hoping those options were added and I'm just missing it.
I should point out, my machine is a Camsoft to Mach3 conversion. The spindle in Camsoft works fine. It's handled using SHW and OFW commands to enable and set the spindle voltage. All OFW commands are 0 to +10V, not negative.
If the Galil driver doesn't do this, I'll try writing a Galil built in program that monitors the spindle voltage and converts any negative voltages to positive voltages (if _OFW < 0, OFW = @ABS(_OFW) sort of thing). This only works if the Galil driver does not monitor the _OFW value. I hate to mess with the Galil driver like this without knowing exactly how the driver handles this.
Thanks,
Mike