@wvreeven thanks for your reply and good to hear this works for you and your devices.
Perhaps @Patrick can fill us in on how device specific this behavior seems to be.
Just to be sure, as after re-reading my original posts this might be confusing, the following works for you?:
- Everything (phidgets, devices, Mac) is powered down
- The USB cable is already connected from Phidgets to Mac
- Power up Phidgets + devices
- Power up Mac and boot into OSX El Capitan
- Start your (custom-) phidgets controlling software
For me, this doesn't work in this order: I need to unplug and replug the USB cable to the Phidgets only after the Mac is fully booted up for any Phidgets software to work.