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wattpeak asked

EM 530 loosing communication for no reason

Good day, My system works as an AC Coupling battery. one external meter measures the HUAWEI PV inverter which is connected to the AC IN 1 branch. This meter is connected to USB #1 The second meter, the one I have a problem with, is the Carlo Gavazzi EM 530. This electricity meter is installed at the position of overflow into the distribution network. It is set to 200A measuring current transformers. This electricity meter is located on usb no. 2. Both electricity meters have the Baud rate, stop bit, and parity set correctly. the problem occurs when the system is started, so the EM530 grid electricity meter stops communicating after a while and there is a delay of several seconds to minutes when the system does not work. see the video. Is it possible that the CERBO GX element is bad? Converter? or it is a wrong setting. Thanks for the help, I'm already very clueless and spent dozens of hours on this problem..



cerbo gxEnergy Meterac coupling
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Duivert NL answered ·

Hi what usb converters are you using?

Whats the cable lenght and what type of cable if extended?

Did you try to terminate the rs485 bus?

Did you try to swap the usb converters from one meter to the other? Same result?

Swap meters on usb ports, same result?

Are there usb hubs in between?

Did you try to give them different rs485 adresses (1 or 2, standard both are 1)?

Lot of questions :)




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wattpeak answered ·

HI,


i have original accessories VICTRON USB-RS485 converter. I shortend it to 10cm of original cable and the rest of route (aprox 70m ) is cat 5E FTP cable.


i try everything. problem should be the long distance aprox 60m. Cable is extended by FTP cable. i try everything what you said but thats not working 100%.

I tried terminate communication with 220Ohm resistor on meter, but there was not any communication between Cerbo and Meter. It works only if i connect 1 pair of cables to meter.

only A and B of communication cable.


I can't understand how it is possible that it runs for 5 minutes without any problem and then suddenly it doesn't, it doesn't seem like a fault in the cable line to me...

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Duivert NL avatar image Duivert NL commented ·

Victron claims a max of about 30m, but rs485 can go to 300m with good quality 110ohm digital cable, you could consider rs485/modbus over utp extenders

220ohms is to high, 120ohm is the terminator value for rs485

But the em530 has an inbuilt terminator, so no need for resistors

just connect 7 to 8 see:

img-6426.jpeg

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wattpeak answered ·

Hi,

thanks. Yeah, i have manual from EM530. i will try it.

BUT - I know some cases from my experience , that some RS485 lines can also work with CYKY type cables for 100meters. ( another technology)


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wattpeak answered ·

Since the communication is stable for example 10 minutes at a time. I'm starting to suspect that the CERBO GX or both converters are bad.


When connecting the termination to pin 7 according to your post, the communication immediately stops working.

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wattpeak answered ·

it's ok, that both meter have same VRM instance?

couldn't be this the major problem?



i will try to change another CERBO to instalattion.

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