Ok great. thanks for the info..

Success I think... I can change the Hz alue with the up and down arrows.. and when I click run all is well...

You don't happen to have any info/manual for this unit do you?

If I wanted to run it with a relay, is it a case of shorting FWD to GND? To stop it, opening that short?

To control the speed, with a pot or software, is it a case of feeding in 0-10V to the '10V IN' (referenced to the GND of course)
For a pot, can I use the '10V out' for a voltage divider?