E16V3 - No reply if command issued just after another command to another device on th

[ldebacker]

it's normal. after sent first command, need wait delay time to send second command.
the delay time according to RS485 baud rate. such as if you use 9600bps or 19200bps, must need wait >20ms.

Actually, this is first command sent to the E16V3 device which poses problem. 

The issue is that the E16V3 does not answer to the command ...
... if there was, shortly before, activity on the bus for another device (a command was sent before to another device, and that the E16V3 should not be concerned about it).

so, in my opinion, this is not normal. 

The RS485 standard specifies a guard time (inter-frame delay) between the reception of the response and the next command of 1.75ms.

This is respected in my case and only the E16V3 has issues with this (it does not cause any issue for other devices on the same RS485 bus).