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matthias-x asked

Multiplus MK3 communication for ESS

Hello,

I´m trying to create my own ESS system with Multiplus 2 and own control software. I just want to tell the device that it should take or feed xxx Watt to/from grid.

Here is my setup:

  • Multiplus 2 3000W 48V

  • MK3-USB Interface

  • Simple serial pc tool in order to see the communication (HTERM)


I already read the documents:

  • ESS mode 2 and 3

  • Interfacing with VE.Bus products – MK2 Protocol


What I´ve done:

  • Set the grid to AN4105 – Internal NS

  • Installed the ESS assistent 017E


In general, I can communicate with the device. I can read DC Info, AC Info.

From the documents above, I think I have to find the RAM ID of the ESS assistant and then just write the set point. Here is what I get (without CRC):


Read RAM ID 128:

05 FF 57 30 80 00 → 07 FF 57 01 00 89 5C

means: Assistent 0000 with 1 RAM ID? (and ~230V AC)


Read RAM ID 130:

05 FF 57 30 82 00 → 07 FF 57 54 00 89 5C

means: Assistent 0005 with 4 RAM ID? Is this the ESS assistent? The manual says that it has only 2 RAM ID? Or do I have to look for the installed 017E assistent?


Read RAM ID 135:

05 FF 57 30 87 00 → 07 FF 57 A1 00 89 5C

I´ve checked also higher RAM ID, but they bring a 00 00.


When I try to set a RAM adress I get a 0x80 error:

Set RAM adress 128+1:

05 FF 57 32 81 00 → 04 FF 57 80 00

Set RAM adress 130+1:

05 FF 57 32 83 00 → 04 FF 57 80 00

write Data to RAM ID (setpoint 200W):

05 FF 57 34 C8 00 → 04 FF 57 80 00


Where is my mistake?


Thank you.


Multiplus-IIcommunication protocolMK3
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1 Answer
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matthias-x answered ·

I´ve got new information:

This link helps:

https://community.victronenergy.com/questions/129947/problem-implementing-the-example-364-from-the-ess.html

- It seems that I have to power off and on the device after I´ve used the victrion control tools. After restart, I didn´t get the 0x80 error.

- The setpoint command has to be repeated every several seconds (maybe 10?), otherwise it will switch to zero.

@ victron

please update you´re documents. I lost a day with googling and playing with the commands.

The ESS assistant seems to have now 4 RAM ID, the manual says just 2. what are the other for. Can you please describe the current meaning of the ID. There is also no information in the changelog.

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