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chrisu asked

Multiple RS485 Devices on Victron USB Dongle?

Hello,

I have a MP2 GX running ESS with the USB->RS485 Converter from Victron. This is connected to the ABB B23 Smart Meter which I need for running the ESS. (system is working properly)


I recently bought a Heat Pump, this also has a RS485 Interface with A B Wiring. I remember that I can connect multiple Devices parallel to the RS485? But they will need the same baud rate, parity?

The ABB Meter is connected with 3 wires, the heat pump has only 2 wires. Will this work?

I just looked at the ABB B23 Documentation, and cant find any info about setting a Device ID, but I think this is nescessary.

Or is it a better idea to use a second usb converter, does this work with a GX device?


Thanks for your help


cerbo gxrs485
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5 Answers
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matt1309 answered ·

I'm not familiar with the meter you're referring to but you're correct in theory using multiple RS485 devices with one USB adapter should work as long as the IDs are different.

However if it's causing you headaches a second RS485 to USB will also work (assuming the RS485 devices are supported by venus os/cerbo gx)

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usernamepasswordbs avatar image
usernamepasswordbs answered ·

Would you just wire the two devices in parallel at the RS485 converter?

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matt1309 avatar image matt1309 commented ·

That's what i thought would solve the problem. The only thing you'd need to watch out for is that the devices dont have the same ID as that can cause conflicts.

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usernamepasswordbs answered ·

So I have wired my Dingtian relay box RS485 in parallel with my ET112 meter. The meter seemed to lose its connection with VRM and the readings were implausible. Also the Multiplus went into Pass-through mode so I deactivated the relay board.

I will try to look at baud rates and IDs next.

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wawibu avatar image wawibu commented ·
@usernamepasswordbs were you able to get it managed? Try to connect multiple devices as well via RS485 and don't want to buy a dedicated adapter for each devices - as that would be against the RS485 idea.....
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usernamepasswordbs answered ·

Hi, I did get it sorted, I mean I have a functioning Dingtian relay box and ET112 but I will get back to you tomorrow with the details: I can't remember off the top of my head !

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usernamepasswordbs answered ·

In fact I connected the Dingtian relay via ethernet cable to my internet router and also the Cerbo is connected to the router via ethernet cable. The ET112 is connected to the cerbo on it's own RS485/USB adapter so in the end I only have one device connected via RS485.

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Related Resources

Cerbo GX product page

GX family product range

Cerbo GX & GX Touch datasheet

Cerbo GX Manual

Venus root access document

Additional resources still need to be added for this topic