Hi Mark,
Not to worry. The analog voltage output and the run signals from the PMDX-107 are both fully isolated from the host computer and from each other. This makes it possible to connect both the Agnd and the COM from the PMDX-107 to the same GND terminal on the AskPower VFD without violating any grounding rules.
It is a bit confusing that the chart from page 11 of the AskPower manual shows only one terminal labeled GND whereas the wiring diagram from page 5 shows 3 different GND terminals.
In your case you should use the following connections:
AskPower PMDX-107
12V OUT Aref
10V IN Aout
GND Agnd, COM
FWD Fwd/Run
REV Rev/Dir
You will need to set some parameters, including one to tell the AskPower to look for its analog speed control voltage on the 10V IN terminal, and another to tell it to look at the FWD and RUN terminals instead of its front panel for start signals.
It is likely that the GND on the 16 pin terminal strip of the AskPower is not the same ground as the main safety ground and I would not recommend connecting them together unless you find a specific mention of that somewhere in the AskPower manual.
If you do find the entire manual in PDF form, we would like a copy for our files. If it is over 5 megabytes, please send it to our support email address as an attachment rather than post it here.
Steve Stallings
