Pressing multiple buttons on battery z-wave switch at the same time blocks whole Z-wave network

Configuration Z-Wave
1

This is my whole setup:

  • Bunch of Aeotec Nano Dimmers spread out throughout whole appartment. Dimmers that I want to control with the switch are within ~3m line of sight from z wave stick.
  • ZHS03 battery switch, located within ~3m line of sight from the z wave stick. It sends central scene commands to HA (I had to edit xml files to receive events)
  • Aeotec Z wave stick

Nano dimmers themselves work perfectly. I can click on the toggle buttons in HA’s interface as fast as I can and lights will keep up with my clicking, turning off/on at fast rate.

Pressing the ZHS03 switch buttons one at a time at slow pace also works, albeit a bit slow (whole second delay between pressing a button and light toggling - delay seems to be mostly switch taking its time to wake up). Switch is linked to the lights via HA 0.92.1 with simple automation (central scene event triggers light toggle service).

However the issue starts when pressing both sides of the switch at the same time (for example if user wants to turn on both lights, he would just press both sides of the switch with two fingers simultaneously). At that point, there is a chance that this event would block entire Z-wave network for few seconds:

  • No commands would go through (either through the switches or through HA interface)
  • Z-wave logs indicate that first central scene is received, but when attempting to relay this to the nano dimmers, messages fail with following messages:
    • CAN received...triggering resend
    • ERROR: Dropping command, expected response not received after 1 attempt(s)
    • WARNING: ZW_SEND_DATA failed. No ACK received - device may be asleep.
    • Here is full log of one such occurence: https://pastebin.com/SfKSTyzs
  • After few seconds, attempted commands would sometimes go through, sometimes not

From what I understand, first button press is sent to the Z-wave network, but until it can be fulfilled, second button press comes in and causes packet collisions. But is Z-wave really so bad that it can only handle one request at a time? I know it is low-bandwith network, but this is pushing it.

Does anyone have any idea what could be causing this? What steps could I take to investigate this issue further?

2

If anyone else stumbles onto this post: I have managed to significantly improve the situation by:

  1. Removing the switch from the controller and re-adding it as non-secure device. From what I read, this generates less overhead and I’m not particularly concerned about security for buttons (worst case, somebody can toggle the lights without my permission or know whenever I’m turning on the lights)
  2. Configuring the switch to use normal scene commands instead of central scene.

Not sure if both helped or just one helped, but after doing those, switches perform much faster and smoother.