Arduino project interfacing with 220V DC inputs and ouputs

[Yoshidk]

Hello
I need the arduino to function as a Set/Reset relay (actualy 7 relays, but lets keep it simple for now).
When I activate the Set-command, the feedback must be latched high for "Q", and when Reset-command is activated "Q" will go low and "Q'" will go high

Please see attachment for a sketch

My problem is the device interfacing with the arduino only can send the commands with "220V DC +"
And to read the "Q" state, 220V DC must be applied.

So my question is, how do I downscale the voltage from 220V DC to 5V DC for the commands
And how do I upscale the voltage from 5V to 220V DC for the feedback from the arduino?

I see the SRD-05VDC-SL-C relay is common in projects, but I believe this can only upscale the voltage, and only to 30V DC 10A, though im not anywhere near 10A.

[septillion]

First question, what weird device gives 220V DC? What the....

For 220V -> 5V I would just use a optocoupler with a resistor.

For 5V -> 220V a relay would be fine. But just get a relay with a 220VDC rating. Doing it with a optocoupler and transistor should also work.

[Yoshidk]

Well, this is for HighVoltage Switchgear. In the switchyard there is a 400kV disconnector, which opens when the open-coil is applied 220V DC and same thing for close-coil. It provides feedback for the "position", one output is high when closed, another when its open.
To manage these signals (and other things) we use BayControllers (Google ABB REC670 or Siemens BC1703 for more inforation), the baycontrollers are typically placed far from the switchgear, to deal with EMC and because we use enourmous batteries for backup, we use 220V DC for everything.

My job is to program/configure those baycontrollers and when im in the testing facility I dont have the highvoltage switchgear so I want to simulate it those so I can get an actual automatic feedback when I give "Close commands (Set)" and "Open commands (Reset).

Im having trouble finding optocouplers and relays for 220VDC rating, do you know where I can find this?

[septillion]

For the 220V -> 5V any regular opto will do. Just place the right resistor in line. You barely need current on the Arduio side so you can get away with a poor CTR. 1mA through the led should work just fine.

They other way around is indeed more difficult because a lot have a Vce lower then 200V... But you could try a staged design with transistors to handle the 200V.