Hey Steve,
I’ve learned a few things about USB interface. I’m using the automation direct serial to USB adapter. First you need to pay attention to the communication setup. I used the default for the DL105. Which is 9600 baud, 8 bits, odd parity and one stop bit. Next you need to decide which port on the DL105 to use. I started with port 1. That is where I think my problem started. It seemed to work fine for outputs but wouldn’t read inputs. I changed to port 2, I also used slave address 1 in Mach while setting up the functions. And everything is working fine. I am finding that if you change USB ports in your computer It changes the com port in your device manager, it can increase the port higher than port 4 which is the highest you can use in Mach. I’m not real happy about that, so I ordered a PCI serial card. I hope this helps others.
Thanks
Art