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janvi avatar image
janvi asked

Connection of ABB B24 Energy Meter fails

Have a energy meter ABB B24 and like to connect to Venus 3.0.0. As far as I understand, it is not possible to chain this into the VE-Bus from Cerbo to MP2. It requires a seperate RS485->USB cable for connection from meter to Cerbo.

The local meter display counts fine and I set the RS485 to Modbus (not EQ), 38k4 and no parity. Address is 1 but possibly a dont care. Nothing more to setup ?

Unfortunately, the RS485 pin count is from left right to left in the instruction book, while it is printed from right to left at instrument.

I expect the counter in the Cerbo Menue Device List but unfortunately nothing appears there and MP2 goes into passthrough without counter information.

As we can see, the cable with FTDI chip enumerates well and opens ttyUSB0:

root@einstein:~# lsusb
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 003: ID 0bda:d723 Realtek Semiconductor Corp.
Bus 005 Device 002: ID 0424:2422 Standard Microsystems Corp.
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@einstein:~# lsusb
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 003: ID 0bda:d723 Realtek Semiconductor Corp.
Bus 005 Device 002: ID 0424:2422 Standard Microsystems Corp.
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@einstein:~#

The HW connection looks like this:


dscf6686.jpg

cerbo gxEnergy Meterrs485
dscf6686.jpg (721.0 KiB)
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4 Answers
janvi avatar image
janvi answered ·

In the meantime the problem is solved. The FTDI RS485 cable uses pin A for Data+ (none inverting) while ABB defines A für Data- (inverted data). Further the ABB manual is useless for the RS485 pin description. The ABB manual shows mirrored connector and labels A,B,C do not define plus and minus as well as the useless pin numbers 35,36,37.



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janvi avatar image
janvi answered ·

After further investigations I have to submit a serious warning for the USB cables above. The matter occupied me 3 weeks and 3 days trouble to examine 10 pcs from diffrent German dealers. The USB cables were advertised as a toy for use with Rasberry Pi. Most work at 9k6 but rarely with 38k4 what is required for the ABB counter. The reason is, that my USB cables contain really lousy fake chips:

https://axotron.se/blog/non-functional-arduinos-from-banggood-com/

https://ftdichip.com/wp-content/uploads/2020/08/Counterfeit-statement.pdf

USB enumeration is without problem, but serial data stream contains junk. The FTDI drivers do not recognize anything. Buffers are delayed randomly to flush and NUL characters including framing errors are inserted here and there. This bug hunting is no matter for beginners.

I bought some of the cables at Reichelt:
https://www.reichelt.de/raspberry-pi-usb-rs485-schnittstelle-ch340c-rpi-usb-rs485-p242783.html

and the remainder at German webshop run by a Chinese:
https://eckstein-shop.de/QITAUSBRS485KonverterBusAdapterSeriellSchnittstelleRaspberryPi


Again, congratulations to the developer team at Victron. Your products simply work like expected.


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Sven Bluege answered ·

@Janvi There is not much information out there regarding those energy meters. Do you know accidentally how often the Cerbo will get measurements from the B24? Background of the questions: getting a B24 now or wait for the vm-3p75ct.

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janvi avatar image
janvi answered ·

I estimate about 1Hz update rate from the B24. Anyhow, this seems not the limiting thing for zero feed in to grid. The Mulitplus are limited to a maximum change rate of around 400 Watt/sek what always causes some unwanted feed back in case of sudden load changes. This change rate is possibly for the grid regulations code and I dont know how to make this faster. Maybe some Victron specialits may have any advice therefore ?


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Sven Bluege avatar image Sven Bluege commented ·

Thank you! Usually, I have less than 400W load per phase but constant change. With the Shelly 3EM I currently get 2Hz, but only with a crappy Wifi connection. So I get a B24 now, which hopefully works before jumping to the new Victron meter or getting my EM530 reading fixed. I smell money burn;)

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