I have the following application:
I try to send RS485 data signal together with 48V/1A supply Voltage over two wires.
The data signal is electricaly isolated via 680µH inductors and 10µ capacitors.
My Data transceiver modules are connected together in a daisy chan. In every transceiver modul is a relay which can switch the Data/Voltage signal path on and off.
Due to the switching there are spikes at the Data signal (after the capacitors) with about 20V high and 50µs long.
I allredy have varistors (5V) at every data signal against GND and between them.
Stil some SN75HVD3082E are dying after some switching cycles.
Are there RS485 transceiver which a more tough against spikes or can someone recommend external components to protect the transceiver aginst them which are not disturbing the RS485 signal.
Thanks, best regards.