You are correct in that you do not need an Echo. But you still need to purchase the portal and you are restricted to issuing commands using the included Bluetooth microphone which has a range of less than 30'.
I tried with a different Echo. Same results, the Alexa app does not include an ISY among those in Connected Home. I suspect that a second portal is required which, in turn, requires a second ISY. I was hoping for a less costly solution.
Which specific H-D motor? Which battery pack? Which controller? Provide as much information as you can. BTW, not pertinent to you dilemma, but how long do the batteries last? Are you using lithium batteries? How often do you move blinds?
I added a 2nd Echo account following these instructions:
1. Get a new Amazon Account and tie your 2nd Echo to the new Amazon account 2. In ISY Portal: a. Create a Subaccount under your account b. Create a different user under your new Subaccount c. Add your ISY to the new Subaccount d. Go to Admin Console | Portals | Approve the access from the Subaccount e. Login to ISY Portal using the subaccount credentials f. Follow the same procedures for linking ISY Portal to Echo but this time use the Second Amazon account (#1)
Everything went well until I opened the new Alexa account. Link to ISY doesn't appear at all.
Edit: now nothing works, not even the original two Echos.
The sensor does respond to both open and close. The sensor will send an on when opened and an off when closed. If you want another device to turn on when the sensor is closed, then you can do that with a program.
The cable distance between the ISY and PLM should be 6' or less. The distance between the ISY and router can be longer. There is no advantage to using Cat6 over Cat5 for the ISY.